* Egypt-mediated ceasefire talks broke down this week
* Israeli air strikes kill nine Palestinians - health officials
* Comes after Palestinian mortar bomb kills Israeli boy (Adds rockets from Syria)
By Nidal al-Mughrabi and Yasmine Saleh
GAZA/CAIRO, Aug 23 (Reuters) - Egypt called on Israel and the Palestinians on Saturday to halt hostilities and resume peace talks, but both sides kept up attacks, including an Israeli air strike which destroyed a residential tower block in the center of Gaza City.
Hamas militants also fired rockets at Israel, hitting the southern city of Beersheba, where two people were hurt, police said. At least two rockets were also fired from Lebanon into northern Israel, but it was not initially clear who fired them, Lebanese and Israeli sources said.
At least five rockets fired from Syria also landed at various locations on the Israeli-occupied Golan Heights, the Israeli army said. All fell in open areas, causing no injuries or damage. It was not immediately known who fired the rockets.
Initial reports said 17 people were wounded in the attack on the 13-story Gaza building, local health officials said.
An Israeli military spokeswoman said the building, which collapsed completely, contained a command center belonging to Hamas militants. Local residents said it housed 44 families.
Another Israeli strike later destroyed a commercial center in the southern Gaza town of Rafah and three people were hurt, local medical staff said.
Five Palestinians, including two children, were killed in another Israeli strike on a house in central Gaza, health officials said. Seven more Palestinians were killed in other strikes, including one on a car.
The Israeli military said it bombed about 20 targets across the Hamas-ruled strip, including rocket launchers and weapon caches next to schools.
No Israeli casualties were reported on Saturday, although rockets and mortar bombs rained down on Israel throughout the day, including one intercepted over the Tel Aviv area, the military said. At least 570 rockets have been fired at Israel since a ceasefire collapsed on Tuesday, it added.
Palestinian health officials say 2,083 people, most of them civilians, have been killed in the small, densely populated coastal enclave since July 8, when Israel launched an offensive with the declared aim of ending Palestinian rocket fire into its territory.
Sixty-four Israeli soldiers and four civilians have been killed.
Indirect ceasefire talks mediated by Egypt to end the conflict collapsed after rockets were fired from Gaza during a truce and Israel responded with air strikes.
The Egyptian Foreign Ministry on Saturday called on both sides to resume talks. Palestinian President Abbas, in Cairo after meeting President Abdel Fattah al-Sisi, also urged a swift resumption of negotiations.
A senior Egyptian diplomat said Abbas had informed Sisi that Hamas was prepared to come to Cairo for further talks, but Hamas did not immediately confirm the report. Israel also had no immediate comment.
The Egyptian diplomat said Cairo expected to receive responses from both Israel and Hamas by Monday.
The talks, conducted in Cairo, have not involved direct meetings between Israeli officials and representatives of Hamas. Israel considers Hamas a terrorist organization and Hamas, for its part, refuses to recognize Israel. Egyptian officials shuttle between the two sides.
Hamas has said it will not stop fighting until the Israeli-Egyptian blockade on Gaza is lifted.
Both Israel and Egypt view Hamas as a security threat and are reluctant to make sweeping concessions without guarantees weapons will not enter the economically crippled enclave.
The Cairo talks had aimed to secure a lasting deal to open the way for reconstruction aid to flow into the Gaza territory of 1.8 million people, where thousands of homes have been destroyed.
"My main goal is for the truce talks to resume in Egypt as soon as possible to avoid more casualties," Abbas said in Cairo.
Hamas spokesman Sami Abu Zuhri said the movement was "in favor of any real effort that will secure the achievement of Palestinian demands and we will study any proposal when presented."
Saturday's violence took place a day after a four-year-old Israeli boy was killed by a mortar attack from Gaza, leading Prime Minister Benjamin Netanyahu to threaten to escalate the fight against Hamas. The boy was the first Israeli child to have died in the conflict.
The United Nations says about 400,000 Gazans have been displaced and more than 400 children killed in the longest and deadliest violence between Israel and the Palestinians since the second Intifada, or Palestinian uprising, a decade ago.
Israel pulled ground forces out of Gaza more than two weeks ago, after saying they had destroyed a network of Hamas tunnels used for cross-border ambushes. But Netanyahu last week granted provisional approval for the call-up of 10,000 army reservists, signaling the possibility of heightened military action.
Hamas leaders said on Saturday they had signed off on Abbas' bid to join the International Criminal Court (ICC), a move that could open both Israel and the militant group to war crime probes over the Gaza conflict. [ID: L5N0QT066]
If the Palestinians were to sign the ICC's founding treaty, the Rome Statute, the court would have jurisdiction over crimes committed in the Palestinian territories. An investigation could then examine events as far back as mid-2002.
Israel and Hamas have traded accusations of war crimes and both defend their military operations as consistent with international law. (Additional reporting by Maayan Lubell and Ori Lewis in Jerusalem and Sylvia Westall in Beirut, Writing by Maayan Lubell and Ori Lewis,; Editing by Ralph Boulton and Dan Grebler)
In the Gaza City strike, a huge fireball followed by a black column of smoke rose into the sky after two Israeli missiles toppled the Zafer Tower, one in a group of several high-rises in the upscale Tel al-Hawa neighborhood. Neighboring buildings shook from the blasts.
The Israeli military said the missiles targeted a Hamas operations room in the building, but did not explain why the entire tower with 44 apartments was brought down.
Gaza police said a warning missile had been fired five minutes earlier and that some residents were able to rush out of the building in time. Still, 22 people were wounded, including 11 children and five women, according to Gaza hospital officials.
Maher Abu Sedo, an area resident, said the two strikes came within seconds of each other.
"People started shouting Allahu Akbar, and women and kids were screaming," he said. "This is crazy. The state of Israel has resorted to madness. In less than a minute, 44 families have become displaced ... They lost everything, their house, their money, their memories and their security."
Some 100,000 Gazans have become homeless, with more than 17,000 homes destroyed or damaged beyond repair, according to U.N. figures. However, Saturday strike marked the first time an entire apartment high-rise was destroyed.
Elsewhere in Gaza, an airstrike on a car killed a man and wounded 11 people, said Ayman Sahabani, head of the emergency room at Gaza City's Shifa Hospital. The Popular Front for the Liberation of Palestine later identified the man killed as a field commander.
Meanwhile, Gaza militants fired over 100 rockets and mortar shells at Israel on Saturday. The barrage came a day after a mortar shell from Gaza hit a farming village in southern Israel, killing a 4-year-old boy.
Israeli media said large numbers of residents of southern Israeli communities near the Gaza border were leaving their homes and heading for safer areas following the death of the boy in Kibbutz Nahal Oz.
"I say whoever can leave, whose presence is not crucial should leave," said Minister of Public Security Yitzhak Ahronovich during a visit to the south on Saturday.
Defense Minister Moshe Yaalon called on southern residents to be ready for a prolonged campaign against Hamas militants.
"In the end we will win," he said Saturday. "This is a test of staying power and strength."
Since the fighting erupted on July 8, Israel has launched some 5,000 airstrikes at Gaza, while Gaza militants have fired close to 4,000 rockets and mortars, according to the Israeli military.
More than 2,100 Palestinians, including close to 500 children, have been killed, according to Palestinian health officials and U.N. figures. Israel has lost 64 soldiers and four civilians.
Israel says it is targeting sites linked to militants, including rocket launchers, command centers and weapons depots. The U.N. says about three-fourth of the Palestinians killed have been civilians.
A formula for ending the war remains elusive.
Hamas demands that Israel and Egypt lift a Gaza border blockade they imposed in 2007, after Hamas seized the territory from Western-backed Palestinian President Mahmoud Abbas.
Israel says it can ease, but not remove the stifling restrictions on Palestinian trade and travel unless Gaza militants agree to disarm and stop manufacturing or smuggling weapons. Hamas has rejected that demand.
During stop-and-go truce talks, Egypt has presented compromise proposals, including a gradual easing of movement for people and cargo at two crossings between Israel and Gaza. However, Israel offered no specific commitments, and Hamas rejected the idea.
Abbas has urged Hamas to accept the plan, which would also give him a new foothold in Gaza because forces under his command would be deployed at the border crossings.
Abbas met Saturday with Egyptian President Abdel-Fattah el-Sissi in Cairo to try to find ways to resume truce talks. After the meeting, the Egyptian Foreign Ministry urged Israel and Hamas to agree to an open-ended cease-fire and resume indirect talks. Egyptian officials did not say how they expected renewed talks to produce a different outcome after repeated failures.
Israeli Prime Minister Benjamin Netanyahu blamed Hamas for the collapse of the most recent cease-fire. In a phone conversation with U.N. Secretary General Ban Ki Moon, Netanyahu alleged that Hamas has violated 11 cease-fires since the war started, Netanyahu's office said.
Israeli government spokesman Mark Regev had no immediate comment regarding the renewed call for a cease-fire. Sami Abu Zuhri, a spokesman for Gaza's ruling Hamas, said the group would consider the Egyptian appeal, but there was no sign it would budge from longstanding demands.
Earlier Saturday, Hamas announced that it has signed a pledge to back any Palestinian bid to join the International Criminal Court. Such a bid could expose Israel, as well as Hamas, to possible war crimes prosecution.
Hamas had hesitated for weeks before giving its written consent. Its decision could further increase domestic pressure on Abbas to turn to the court.
Abbas has debated the issue for months, since seeking ICC action could transform his relations with Israel from tense to openly hostile, strain his ties with the United States and deprive his government of badly needed Western financial support.
Last month, Abbas said he would not make a move without the written consent of all Palestinian factions. He obtained such support from all groups represented in the Palestine Liberation Organization, while Hamas, not a PLO member, said it would study the idea.
It remains unclear if Abbas will turn to the court, now that he has Hamas support in writing. An Abbas aide said last week that no decision would be made before March when a U.N. commission of inquiry into possible war crimes committed in the Gaza war is to hand in its findings.
Enav reported from Jerusalem. Associated Press writers Mohammed Daraghmeh in Ramallah, West Bank, Ibrahim Barzak in Gaza City, Gaza Strip and Sarah El Deeb in Cairo contributed to this report.