Obama apologizes over Quran burning

Photo caption: Afghan demonstrators burn a U.S. flag during a protest against Quran desecration in Helmand province today, the third day of violent protests that have left at least 12 people dead.

Barack Obama has written a letter formally apologizing for the burning of copies of the Quran at a coalition military base in Afghanistan, the Afghan president's office said today, amid reports that two American troops had been shot dead.

A man dressed as an Afghan government soldier killed the soldiers and wounded four others during a protest about the burning of Islamic holy books that had been used by detainees held at the Bagram military base, a police officer and a provincial Afghan official told NBC News.

There have been violent protests every day since the news of the Quran desecrations emerged on Tuesday in what has become a public relations disaster for foreign forces in Afghanistan.

In the letter, which is quoted in the statement, the U.S. president expresses his "deep regret for the reported incident" and offers his "sincere apologies."

According to the statement, Obama wrote: "The error was inadvertent; I assure you that we will take the appropriate steps to avoid any recurrence, to include holding accountable those responsible."