CNN Security Clearance

Obama apology doesn't halt Afghan violence

Afghan rage over the burning of Qurans by NATO troops showed little signs of subsiding Thursday even after a President Barak Obama apologized for the "error."

In a letter delivered to Afghan President Hamid Karzai, Obama called the act "inadvertent," Karzai's office and National Security Council spokesman Tommy Vietor said Thursday.

"We will take the appropriate steps to avoid any recurrence, including holding accountable those responsible," Obama said in the letter delivered by Ryan Crocker, the U.S. ambassador to Afghanistan.

Afghanistan erupted in violent demonstrations since the troops' burning of the Islamic religious material at the beginning of the week. Many feared further unrest Friday, the Islamic holy day.