At least six people are reported to have been killed in the second day of protests in Afghanistan over reports that NATO troops put copies of the Quran in a garbage incinerator, according to Reuters.
The news agency said President Hamid Karzai had issued a statement calling on security forces to protect lives and property and for the public to regain its calm.
"Protests are the right of people but I ask my countrymen to avoid violence," he was quoted as saying, urging people to wait for the outcome of investigations into the incinerations.
One person was killed in Kabul, one in the eastern city of Jalalabad and two in Parwan province, according to the BBC. Another 20 people were injured amid demonstrations in Kabul and the eastern city of Jalalabad.
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The US Embassy in Kabul announced it was on lockdown, after warning that protests near Camp Phoenix, a nearby American military base, were turning violent. "Please, everyone, be safe out there," it tweeted.
Several hundred protesters reportedly threw rocks and burned tires near the base. Part of a housing complex used mainly by foreign contracters was also set alight, Reuters reported. Around 1,000 people gathered outside another US base in Jalalabad, while others blocked the highway between the two cities.
The crowds shouted "Death to America" and "Death to [Afghan President Hamid] Karzai," witnesses said. "When the Americans insult us to this degree, we will join the insurgents," one protester in Kabul told Reuters.
Afghan police responded with water cannon, rubber bullets and live shots fired into the air. Doctors told the Associated Press that dozens of protesters were wounded in the gunfire.
Meanwhile more details emerged of the incident that sparked the demonstrators' anger. According to The New York Times, which cited Afghan workers at Bagram Airbase, two American NATO employees threw bags of books, including Qurans, into a waste incinerator late on Monday. They appeared not to realize the potential seriousness of what they were doing until Afghan laborers intervened.
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An unnamed US defense official told the Wall Street Journal that the Qurans had been put in with "extremist literature" found in a prison library at the detention facility in Bagram. Guards believed the material was being used to transmit secret messages between detainees, so they decided to destroy it. "Where it went bad on our end is not properly disposing of the religious material," the official said.
All coalition forces in Afghanistan will be given training in how properly to identify and handle religious materials "no later than March 3," top NATO commander John R. Allen said. The International Security Assistance Force (ISAF) is investigating.
US Defense Secretary Leon Panetta joined Allen in apologizing for the incident yesterday, saying American authorities "disapprove of such conduct in the strongest possible terms."
President Karzai condemned the alleged burning, the BBC said, while the Taliban claimed the incident would offend "one billion Muslims around the world."