KABUL, Afghanistan – Afghans took to the streets for a fourth day Friday to protest American mistreatment of the Quran.

The demonstrations left at least nine people dead and thousands more expressing frustration that after 10 years of war, U.S. troops still don’t understand how to handle a Muslim holy book.

“The foreigners keep testing our faith and our patience by burning the Quran. They want to see if we are good Muslims or not, and whether we show any reaction or not,” one protester said as he marched near Afghan President Hamid Karzai’s palace in Kabul.

For the first time since word surfaced that American soldiers had burned Qurans at Bagram Air Base outside Kabul, protests reached nearly all parts of Afghanistan, with demonstrators chanting “Death to America” and “Death to the infidels.” In the city of Herat, in western Afghanistan, hundreds tried to storm the American consulate. Afghan police opened fire, killing three. Two dozen were injured.

Violence also was reported in the northern province of Baghlan, where one civilian was killed and three were wounded outside a coalition provincial reconstruction team base, and in the eastern province of Nangarhar, where one person was killed.

Six people were wounded in Khost province and two protesters and four police officers were injured in clashes in Kabul.

Despite the violence, U.S. officials in Washington said they were cautiously optimistic that the tensions over the Quran burnings would soon ease.

But they kept U.S. troops on heightened alert and reduced the number of patrols after the deaths Thursday of two U.S. soldiers who were killed by a demonstrator dressed in an Afghan army uniform.