JALALABAD, Afghanistan (Reuters) - A "rogue" Afghan border policeman shot dead two foreign soldiers on a training mission on Monday, and hundreds of people turned out on the streets for a fourth day of protests against the burning of a Koran by a fundamentalist U.S. pastor.
Up to a thousand angry residents in eastern Jalalabad city blocked the main highway to Kabul and set alight effigies of the pastor who presided over the Koran burning, said Ahmad Zia Abdulzai, spokesman for the provincial governor.
Hundreds held peaceful protests in neighboring Laghman and nearby Paktia provinces. In southern Helmand province, residents of Lashkar Gah were coming out for a demonstration when a thwarted suicide attack cleared the streets.
Police spotted two men driving into the central court and opened fire, the Helmand provincial governor's office said.
One was seriously wounded and the other managed to detonate his explosives, wounding one policeman and two civilians, but did not kill anyone.
About 20 people have been killed and nearly 150 wounded over three days of protests in north and south Afghanistan that degenerated into violence, although other large gatherings in some parts of the country ended peacefully.
Twelve people were killed and more than 110 wounded in Kandahar over Saturday and Sunday, where demonstrators waving Taliban flags and shouting "Death to America" burned cars, smashed shops and sacked a girls' high school.
On Friday, seven foreign U.N. staff and five Afghan protesters were killed after demonstrators overran their office in normally peaceful Mazar-i-Sharif city in the north.
The protests were driven by anger at radical fundamentalist Christian preacher Terry Jones, who supervised the burning of a Koran in front of about 50 people at a church in Florida on March 20.
Western political and military leaders, including U.S. President Barack Obama and the top U.S. and NATO commander in Afghanistan, General David Petraeus, have condemned the Koran burning, as well as the violence that followed.
Those condemnations appear to have done little to placate anger or anti-Western sentiments across much of Afghan society.
Jones has been unrepentant about the Koran burning and has since vowed to lead an anti-Islam protest outside the biggest mosque in the United States later this month.
ROGUE ATTACK
The shooting in Faryab of two foreign soldiers who were training Afghan police highlighted another challenge for U.S. and NATO forces as they try to prepare for a gradual handover of security responsibilities that begins in July.
Abdul Sattar Bariz, deputy governor of northern Faryab province, said two American soldiers were killed at a checkpoint by a member of the Afghan Border Police, in what appeared to be the latest in a string of "rogue" shootings.
"He killed the two trainers while they were teaching (Afghan police), in Faryab city," Bariz told Reuters by telephone.
Rapid recruitment into the Afghan security forces, which will be boosted to at least 305,000, has raised fears the Taliban has infiltrated sympathizers into the police and army.
Afghan authorities began tighter vetting of recruits after a renegade soldier killed five British troops in 2009, but there have still been at least a dozen killed in such incidents over the past year.
In February, at least two German soldiers were killed by a man wearing an Afghan army uniform in northern Baghlan province, and last November a border policeman shot and killed six U.S. troops while they were on a training mission.
Earlier that same month three troops from the NATO-led coalition were shot by an Afghan soldier in the south, and in August two Spanish police and an interpreter were killed by an Afghan policeman they were training in the northwest.
The NATO-led International Security Assistance Force (ISAF) said on Monday it was investigating the deaths of two soldiers who were killed inside a base by an attacker who appeared to be from the Afghan police force.
"According to initial reporting, an individual in an Afghan Border Police uniform fired on the ISAF members inside a compound. The individual who fired the shots fled the scene," an ISAF statement said.
The uniform does not prove conclusively the attacker was a policeman because Afghan security force outfits are available in markets across the country -- although their sale is technically illegal -- and insurgents have sometimes worn them for attacks.
General Habib Sayedkhil, a senior border police official in the north, said shots were fired from a house near the base.
One police guard ran away after the attack but there were no bullet casings found at his position, Sayedkhil said, adding that suggested he ran from fear rather than guilt.
"After the shooting the soldier jumped down and ran away to save his life," he said. "There was no evidence that he killed the Americans."
(Additional reporting by Elyas Yaseni in MAZAR-I-SHARIF and Hamid Shalizi in KABUL; Writing by Emma Graham-Harrison; Editing by Paul Tait)
Copyright 2011 Thomson Reuters. Click for Restrictions.