Video from Yahoo news covering the protests
By DION NISSENBAUM
KABUL—Afghanistan is bracing for intensifying protests, as outrage over the burning of Qurans at a U.S. base led to the first American casualties and President Barack Obama vowed to hold coalition officials accountable for the "inadvertent" sacrilege.
Casualty Count
Track the deaths of U.S. and allied forces' troops in Afghanistan and Iraq.
More photos and interactive graphics
The three days of protests against Monday's burning of Islam's holiest book at the Bagram Airfield already have resulted in the deaths of at least 10 Afghans. Demonstrations are expected to escalate Friday, when clerics at mosques around the country are expected to dedicate their weekly sermons to denouncing the incident.
In an attempt to assuage the anger, Mr. Obama apologized to Afghan President Hamid Karzai for what he called inadvertent attempts to burn the Islamic books, in a personal letter delivered Thursday by the U.S. ambassador to Kabul, Ryan Crocker.
"I assure you that we will take appropriate steps to avoid any recurrence, to include holding accountable those responsible," President Obama said in the letter, according to Mr. Karzai's office.
The deadly demonstrations that spread across Kabul and Afghanistan's provinces this week have targeted U.S. and coalition military bases, Afghan government buildings and other symbols of Western presence.
Enlarge Image
Agence France-Presse/Getty Images
Afghan demonstrators run as they shout anti-U.S. slogans during a protest in Kabul Thursday.
Hours after the Taliban called Thursday on Afghans to kill Western forces in Afghanistan to avenge the insult, an Afghan soldier opened fire on U.S. troops on a base in eastern Nangarhar province, according to Afghan officials. Two American troops were killed before the Afghan soldier escaped into a crowd of protesters demonstrating outside the base in the province's Khogyani district.
This week's demonstrations erupted after coalition soldiers brought a truckload of Qurans and other Islamic books from a Bagram detention facility to an incinerator at the base. Afghan workers at the base said they stopped the soldiers from destroying the books, but not before several copies of the Quran had been partially burned.
U.S. military officials have launched an investigation to try to determine why the soldiers tried to burn Islamic materials. These books, according to some U.S. officials, were slated for destruction because they contained "extremist literature" and prisoners' "clandestine communications."
Burning the Quran is a particular affront to Muslims, who view the book as the sanctified word of God as relayed to Prophet Muhammad. In April 2011, after a Florida pastor oversaw the burning of a Quran, angry demonstrators in northern Afghanistan stormed a United Nations compound following Friday prayers, killing seven foreigners.
The memories of last year's attack resonated this week as Western embassies, aid groups and the U.S. military imposed strict travel bans on their staffs and warned foreigners to steer clear of protests. The American Embassy in Kabul on Thursday extended travel restrictions to northern Afghanistan.
Mr. Karzai, who issued on Wednesday an appeal for calm that appeared to have little immediate effect, met with hundreds of Afghan lawmakers Thursday to discuss the crisis. Some of these lawmakers had called Wednesday for a "jihad," or holy war, against the U.S.
"This is a huge crime, and the people involved in it must be punished," said Afghan parliamentarian Mohammad Noor Akbari, who participated in Thursday's meeting with the Afghan president.
The Taliban have sought to capitalize on the widespread outrage by calling for Afghans across the country to attack Western bases, target military convoys and kill soldiers. Earlier this week, they also urged Afghan soldiers to turn their weapons on their Western counterparts.
At the same time, the latest Taliban statement affirmed the insurgent group's support for continuing negotiations with the U.S. to open a Taliban political office in Qatar.
—Habib Khan Totakhil
and Ziaulhaq Sultani
contributed to this article.
By DION NISSENBAUM
KABUL—Afghanistan is bracing for intensifying protests, as outrage over the burning of Qurans at a U.S. base led to the first American casualties and President Barack Obama vowed to hold coalition officials accountable for the "inadvertent" sacrilege.
Casualty Count
Track the deaths of U.S. and allied forces' troops in Afghanistan and Iraq.
More photos and interactive graphics
The three days of protests against Monday's burning of Islam's holiest book at the Bagram Airfield already have resulted in the deaths of at least 10 Afghans. Demonstrations are expected to escalate Friday, when clerics at mosques around the country are expected to dedicate their weekly sermons to denouncing the incident.
In an attempt to assuage the anger, Mr. Obama apologized to Afghan President Hamid Karzai for what he called inadvertent attempts to burn the Islamic books, in a personal letter delivered Thursday by the U.S. ambassador to Kabul, Ryan Crocker.
"I assure you that we will take appropriate steps to avoid any recurrence, to include holding accountable those responsible," President Obama said in the letter, according to Mr. Karzai's office.
The deadly demonstrations that spread across Kabul and Afghanistan's provinces this week have targeted U.S. and coalition military bases, Afghan government buildings and other symbols of Western presence.
Enlarge Image
Agence France-Presse/Getty Images
Afghan demonstrators run as they shout anti-U.S. slogans during a protest in Kabul Thursday.
Hours after the Taliban called Thursday on Afghans to kill Western forces in Afghanistan to avenge the insult, an Afghan soldier opened fire on U.S. troops on a base in eastern Nangarhar province, according to Afghan officials. Two American troops were killed before the Afghan soldier escaped into a crowd of protesters demonstrating outside the base in the province's Khogyani district.
This week's demonstrations erupted after coalition soldiers brought a truckload of Qurans and other Islamic books from a Bagram detention facility to an incinerator at the base. Afghan workers at the base said they stopped the soldiers from destroying the books, but not before several copies of the Quran had been partially burned.
U.S. military officials have launched an investigation to try to determine why the soldiers tried to burn Islamic materials. These books, according to some U.S. officials, were slated for destruction because they contained "extremist literature" and prisoners' "clandestine communications."
Burning the Quran is a particular affront to Muslims, who view the book as the sanctified word of God as relayed to Prophet Muhammad. In April 2011, after a Florida pastor oversaw the burning of a Quran, angry demonstrators in northern Afghanistan stormed a United Nations compound following Friday prayers, killing seven foreigners.
The memories of last year's attack resonated this week as Western embassies, aid groups and the U.S. military imposed strict travel bans on their staffs and warned foreigners to steer clear of protests. The American Embassy in Kabul on Thursday extended travel restrictions to northern Afghanistan.
Mr. Karzai, who issued on Wednesday an appeal for calm that appeared to have little immediate effect, met with hundreds of Afghan lawmakers Thursday to discuss the crisis. Some of these lawmakers had called Wednesday for a "jihad," or holy war, against the U.S.
"This is a huge crime, and the people involved in it must be punished," said Afghan parliamentarian Mohammad Noor Akbari, who participated in Thursday's meeting with the Afghan president.
The Taliban have sought to capitalize on the widespread outrage by calling for Afghans across the country to attack Western bases, target military convoys and kill soldiers. Earlier this week, they also urged Afghan soldiers to turn their weapons on their Western counterparts.
At the same time, the latest Taliban statement affirmed the insurgent group's support for continuing negotiations with the U.S. to open a Taliban political office in Qatar.
—Habib Khan Totakhil
and Ziaulhaq Sultani
contributed to this article.

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