By Richard Balmforth
KIEV, Aug 25 (Reuters) - Ukraine accused Russia on Monday of sending soldiers across the border to open a new front in the separatist war that has devastated the east of the country and provoked the gravest East-West crisis since the fall of communism.
The charge, dismissed by Moscow, dealt a blow to already slim hopes of progress at talks on Tuesday towards ending the conflict between pro-Russian rebels and Ukrainian troops, in which more than 2,000 people have been killed.
Ukrainian President Petro Poroshenko, who is due to meet Russia's Vladimir Putin in the Belarussian capital of Minsk, expressed "extraordinary concern" at the Russian move, his press service said, setting the scene for a possibly angry encounter.
The Ukrainian military said a group of Russian forces, in the guise of separatist rebels, had crossed into south-east Ukraine with 10 tanks and two armored infantry vehicles. It said border guards had halted the column outside Novoazovsk, Ukraine's most south-easterly point on the Azov Sea.
"This morning there was an attempt by the Russian military in the guise of Donbass fighters to open a new area of military confrontation in the southern Donetsk region," military spokesman Andriy Lysenko told journalists.
Donbass is the name given to the industrialized and mainly Russian-speaking east of Ukraine, where two regions -- Donetsk and Luhansk -- have declared independence from Ukraine in an attempt to join Russia.
Lysenko later added that two tanks in the column had been destroyed and several members of "an intelligence-sabotage group" had been seized.
"The area is now blocked by Ukrainian troops," he said.
With the rebels largely encircled in the cities of Donetsk and Luhansk, Ukraine has been pressing its advance while its Western allies have waited nervously to see if Moscow will intervene to prevent the separatists being crushed.
Russian Foreign Minister Sergei Lavrov, asked about the alleged incident, said "I have not heard of this, but there is plenty of disinformation out there about our 'incursions'."
NATO said last week that Russian forces had been firing artillery both within Ukraine and across the border, but Moscow has consistently denied taking part in the fighting or supplying weapons to the separatists.
The latest round of accusations and denials made it even more unlikely that any breakthrough can emerge from Tuesday's talks in Minsk, where Poroshenko and Putin will meet for the first time since early June.
Also taking part will be senior officials from the European Union, which along with Washington has imposed sanctions on Russia for what they criticize as its failure to rein in the separatists. Russia has hit back by banning most Western food imports.
Lavrov repeated Russian calls for a ceasefire and talks between all sides in Ukraine, saying the West should not put all the onus on Moscow.
"I hope very much our Western colleagues... won't just come with expectations we will somehow magically solve things for them. That will not work," he told a news conference.
With Russia blaming the crisis on Ukraine's military offensive and Ukraine refusing to pause its advance until Russia curbs the rebels, the chances of any progress were already looking bleak.
Further complicating the picture, Lavrov said Russia planned to dispatch a second convoy of humanitarian aid to relieve the plight of civilians in eastern Ukraine.
When a first convoy of more than 200 trucks crossed the border without Kiev's permission last week, Ukraine's state security chief denounced it as "a direct invasion".
Poroshenko, in a phone conversation with European Council President Herman Van Rompuy on Monday, expressed "extraordinary concern" at the movement of Russian military equipment across the border though he did not mention Russian soldiers.
His press service quoted him as expressing great disquiet also at "Russia's intention of sending a second so-called humanitarian convoy to Ukraine". He asked Van Rompuy to take joint steps "to stop the war in the center of Europe".
The separatist rebellions erupted in Ukraine's mainly Russian-speaking east in April, two months after street protests ousted a Moscow-backed president in Kiev, replacing him with a pro-Western government.
Russia responded by annexing Ukraine's Crimea peninsula, and Putin spoke of its right to defend the interests of Russian-speakers in Ukraine.
The new military thrust - whether it is by separatist rebels alone or with the aid of Russian soldiers - might be aimed at capturing Mariupol, a government-held port city on the Azov Sea.
But military spokesman Lysenko said the main highway linking Novoazovsk to Mariupol, about 30 km (20 miles) west along the coastline, was still under the control of government forces.
"Novoazovsk has not been seized. The highway is under the control of forces of the anti-terrorist operation. We have enough resources in Mariupol itself to repel any attacks," he said.
Lyudmila, a resident of Novoazovsk who was reached by telephone, said: "Everything began at 8 o'clock this morning. Tanks appeared - no fewer than 7 of them, and Grads (rockets) and armored vehicles."
She said the rebel forces had fired on Novoazovsk from the village of Markine, about 7 km (4 miles) away.
"Novoazovsk has died. People are hiding (from the shelling). We heard rumors of an invasion just a couple of days ago. The Ukrainian flag has been taken down on the city council offices," she said.
The commander of a Ukrainian national guard unit in the area near Novoazovsk where the fighting was reported told Reuters by telephone: "A war has broken out here." He said he could not speak and ended the conversation. (Additional reporting by Pavel Polityuk, Alessandra Prentice and Lina Kushch in Ukraine and Katya Golubkova, Maria Tsvetkova and Gabriela Baczynska in Moscow; Writing by Mark Trevelyan; Editing by Tom Heneghan)
BEFORE YOU GO
09/06/2014 6:08 PM EDT
Factory Ablaze After Artillery Fire Near Mariupol
Prolonged artillery fire was heard late on Saturday to the east of the port of Mariupol in eastern Ukraine, a Reuters reporter said, in what may be the first significant violation of a ceasefire declared little more than 24 hours earlier.
The reporter saw an industrial facility, a truck and a gas station ablaze in an area within the limits of Mariupol, a city of 500,000 people on the Sea of Azov near the Russian border.
The area had seen fierce fighting between Ukrainian government forces and pro-Russian separatists before the ceasefire took effect on Friday evening. It had been quiet since then until the artillery fire began late on Saturday.
"There has been an artillery attack. We received a number of impacts, we have no information about casualties," a Ukrainian officer told Reuters at the scene.
09/06/2014 6:03 PM EDT
Ukraine Battalion: Reports Of Civilian Casualties In Shelling
09/06/2014 6:00 PM EDT
#RussiaViolatedCeasefire Trends On Twitter
Twitter users are using the hashtag #RussiaViolatedCeasefire to blame Moscow for renewed violence in east Ukraine.
Hashtag #russiaviolatedceasefire is now showing up as a suggestion. Good work, fellow Ukrainians— неХуёвый Portland (@the_boris) September 6, 2014
Meanwhile, Lithuanian Ambassador to Sweden Eitvydas Bajarunas used the hashtag for call for more information, as rockets and shelling were reported in the Ukrainian port city of Mariupol.
09/06/2014 5:43 PM EDT
Rockets Fired In Ukraine Amid Ceasefire
Witnesses in the Ukrainian port city of Mariupol are reporting sustained explosions outside the city and a volunteer battalion of Ukrainian fighters says Grad rockets are being fired at its positions.
The reports Saturday night come little more than a day after Ukraine and Russian-backed separatist rebels signed a cease-fire after more than four months of fighting in the country's east.
The cease-fire had appeared to largely been holding during much of the day.
But late Saturday, witnesses in Mariupol told The Associated Press by telephone that heavy explosions were coming from the city's eastern outskirts, where Ukrainian troops retain defensive lines against the rebels.
The volunteer Azov Battalion said on Facebook that their positions were hit by Grad rockets, but did not give details.
09/06/2014 4:49 PM EDT
Reports Of Shelling In Mariupol
BBC journalists Fergal Keane and Will Vernon in Ukraine's Mariupol say that shelling of the port city has resumed.
#Ukraine shelling started at approx 2235 local and is continuing— Fergal Keane (@fergalkeane47) September 6, 2014
#Ukraine On roof of hotel and can see flashes from explosions and hear powerful detonations.— Fergal Keane (@fergalkeane47) September 6, 2014
09/06/2014 12:21 PM EDT
ICRC Says Aid Trucks Forced Back By Shelling
The International Committee of the Red Cross said its aid trucks were forced to turn back on Saturday morning due to shelling in east Ukraine.
09/06/2014 10:59 AM EDT
Putin, Poroshenko Agree Cease-Fire Holding
Russian President Vladimir Putin and Ukraine's President Petro Poroshenko agreed on Saturday in a telephone call that a ceasefire in eastern Ukraine was generally holding but said further steps were needed to make it more durable.
The ceasefire between Ukrainian government forces and pro-Russian separatists took effect on Friday evening, part of a wider peace plan aimed at ending five months of fighting in eastern Ukraine.
"(The two leaders) also stressed the need for the maximum involvement of the Organisation for Security and Cooperation in Europe (OSCE) in monitoring the situation ... and for cooperation in providing Ukrainian and international humanitarian help," Poroshenko's office said in a statement.
09/06/2014 10:58 AM EDT
Rebel Leader: Prisoner Exchange To Take Place Saturday
A separatist leader said that the rebels and Ukrainian government will begin the exchange of prisoners of war, part of the peace roadmap, later on Saturday, Reuters reports. Meanwhile, Kiev said the details of the exchange were still being worked out.
09/05/2014 12:38 PM EDT
Peace Deal Outlined
New York Times Moscow bureau chief Neil MacFarquhar outlines the different aspects of the Ukrainian peace deal.
The Ukrainian National Information Agency released a list of the 14 points included in the cease-fire plan. #Ukraine— Neil MacFarquhar (@NeilMacFarquhar) September 5, 2014
2 some focused on cease-fire itself, some on practical steps to get the government functioning and some on Donbas political future. #Ukraine— Neil MacFarquhar (@NeilMacFarquhar) September 5, 2014
3 The agreement followed almost verbatim a cease-fire proposal first put out by Mr. Poroshenko in June.— Neil MacFarquhar (@NeilMacFarquhar) September 5, 2014
4 14 points include amnesty for all those who disarm and who did not commit serious crimes, as well as the release of all hostages. #Ukraine— Neil MacFarquhar (@NeilMacFarquhar) September 5, 2014
5 Militias will be disbanded, and a 10-kilometer buffer zone established along Russian-Ukrainian border. Area subject to joint patrols— Neil MacFarquhar (@NeilMacFarquhar) September 5, 2014
6 Separatists agreed to leave administrative buildings they control and broadcasts from Ukraine to resume on TV #Ukraine— Neil MacFarquhar (@NeilMacFarquhar) September 5, 2014
7 On future, the agreement said power would be decentralized and the Russian language protected. Region consulted on selection of governor— Neil MacFarquhar (@NeilMacFarquhar) September 5, 2014
8. Early elections and jobs....No mention of a chicken in every pot. #Ukraine— Neil MacFarquhar (@NeilMacFarquhar) September 5, 2014
09/05/2014 12:18 PM EDT
Obama: Hopeful But Skeptical
U.S. President Barack Obama said he was hopeful but skeptical about a ceasefire agreed in Ukraine on Friday and urged European allies to agree on new sanctions against Russia that could be suspended if the peace plan holds.
He also said he was leaving a two-day NATO summit in Wales confident that U.S. allies were prepared to join a broad coalition to take action to degrade and ultimately destroy Islamic State militants in Iraq.
"We also sent a strong message to Russia that actions have consequences. Today the United States and Europe are finalizing measures to deepen and broaden our sanctions across Russia's financial, energy and defense sectors," Obama told a news conference.
NATO had made clear it would defend every ally, and that it supported Ukraine's sovereignty against what he called Russian aggression, he said.
"With respect to the ceasefire agreement, obviously we are hopeful but based on past experience also skeptical that in fact the separatists will follow through and the Russians will stop violating Ukraine's sovereignty and territorial integrity. So it has to be tested," the president said.