Apology 'calmed things down' in Afghanistan: Obama

President Barack Obama said on Wednesday that his formal apology last week to Afghan President Hamid Karzai for the burning of copies of the Koran at a U.S. military base had "calmed things down", after the incident spurred protests against U.S. and NATO troops in Afghanistan.

"I think the reason that it was important ... is to save lives, and to make sure our troops who are there right now are not placed in further danger," Obama told ABC News in an interview before a dinner to honor U.S. war veterans.

The president wrote to Karzai to apologize after Afghan workers found charred copies of the Muslim holy book at the base near Kabul. Muslims view the Koran as the literal word of God and treat each book with deep reverence.

"It calmed things down. We're not out of the woods yet," Obama said of his apology. "My criteria in any decision I make, getting recommendations from the folks who are actually on the ground, is what is going to be best to protect our folks and make sure they can accomplish their mission."