President Obama apologized in a letter and Afghan President Hamid Karzai appealed for calm.
But that was not enough to keep Afghans from protesting violently for a third day following word that several copies of the Muslim holy book, the Quran, were burned at a large NATO base outside Kabul.
The latest incident resembled other cases in recent years, where rumors that a Quran was desecrated — even thousands of miles away in Florida or Guantanamo Bay — ignited deadly riots in Afghanistan.
This time American officials acknowledged the desecrations took place. They say U.S. soldiers accidentally burned several Qurans along with what was considered radical religious materials.
Two Americans Killed
Meanwhile, the Taliban called for attacks on Western troops and any Afghan who works with them. At least one Afghan soldier seemed to heed the message, killing two American troops in the east of the country.
Haji Mohammad Hassan, a district governor from the eastern province of Nangarhar, said about 500 people were protesting outside a joint American-Afghan military base.
Without warning, an Afghan army soldier turned his gun on the Americans, killing two of them. Hassan said several protesters were killed and wounded in the ensuing firefight, but the Afghan soldier escaped into the crowd.
It's the latest in a series of recent incidents where Afghan soldiers killed their NATO trainers, but this one appeared to be directly related to the Quran incident.
Taliban Urge Attacks
Even before Taliban statements encouraging Afghans to rise up against foreign troops in the country, angry mobs clashed with Afghan police in half-a-dozen provinces.
Abdel Satar Barez, deputy governor of western Faryab province, said a peaceful protest by clerics gave way to a mob of 400 that set fire to cars belonging to Afghan civilians who work at a NATO base.
By Thursday evening, Karzai had received the formal apology from Obama and released a statement appealing for calm.
Afghan and U.S. forces are bracing for the possibility of another day of anger and violence. At Friday prayers, clerics often deliver political as well as religious messages. Even some members of the Afghan parliament have called for a holy war against Americans because of the incident.
The commander of American forces has announced that all soldiers will receive training on how to respect religious items. But many Afghans are wondering, after 10 years and several similar riots in the past, how such a mistake could have occurred.