President Barack Obama is extending his deepest condolences to the families and loved ones of those killed in the northern Afghan city of Mazar-i-Sharif by protesters enraged by the burning of a Quran in Florida.
Obama says desecration of the Quran "is an act of extreme intolerance and bigotry."
But he says that does not justify attacking and killing innocent people, calling it "outrageous and an affront to human decency and dignity."
Eleven were killed on Friday, including seven foreign UN employees.
And Afghans rioted for a second day on Saturday, killing nine people in Kandahar and injuring more than 80.
Obama said in a statement that no religion tolerates "the slaughter and beheading of innocent people."
He said now was a time to draw upon the common humanity of all.