Published: Feb 24, 2012 11:49 AM EST

KABUL, Afghanistan (AP) - NATO's top military commander says an investigation into this week's Quran burnings at a U.S. base in Afghanistan is pushing ahead and called on Afghans to be patient and exercise restraint.
 
U.S. Gen. John Allen said in a statement Friday that NATO and Afghan leaders are working together to insure such an incident is not repeated.
 
Afghan security forces are on high alert to deal with expected demonstrations around the country after Friday prayers.
 
The country has been wracked by three days of violence that has claimed 13 lives, including two U.S. soldiers over the burnings of the Muslim holy book.
 
Allen says a joint NATO and Afghan investigation is continuing.