americans injured there were two afghans killed. violence erupted across afghanistan after it was learned that u.s. troops disgoesed of qur'ans accidentally in a fire pit used to burn trash. -- >> it is time now to return to calm and keep. and not to allow the enemies of the people of afghanistan, the enemies of peace and stability of the people of afghanistan, to use this from this time and bring danger to the properties of our people and our country. >> reporter: an estimated 30 people have been killed in a week of violence, including four americans, two gunned down yesterday in the afghan interior ministry in kabul. these two advisers were shot in the back of the head, a manhunt is underway for the suspect. the american ambassador to afghanistan and a key u.s. senator say the mission in afghanistan must continue any way. >> again, these are terrible tragedies.