Afghan officials say at least seven people were killed in clashes between Afghan security forces and demonstrators protesting for a second day against the burning of copies of the Quran at a NATO military base.

Officials say dozens of others also were injured at protests held in the capital, Kabul, Parwan province and the eastern city of Jalalabad.

VOA reporters in Jalalabad saw Afghan security forces in riot gear face off against protesters, who were throwing stones and setting fires. Police also used water hoses from vehicles to try and control the crowd. One protester at the scene told VOA that police had opened fire from a checkpoint and hit one of his friends.

Protesters told VOA that they want the Americans out of their country and that words alone cannot change the disrespect that Muslims have suffered.

Meanwhile, crowds in the capital, shouted chants of “Death to America” while hurling stones at officers, setting fire to cars and buildings and blocking some main roads. The protest prompted the U.S. Embassy to place its staff on lockdown and suspend all travel.

U.S. Deputy Defense Secretary Ashton Carter met Wednesday in Kabul with Afghan leaders, including President Hamid Karzai, to again apologize for the incident.

A day earlier, the commander of the international coalition, U.S. General John Allen, issued an apology and ordered an investigation into the report that coalition forces “improperly disposed” of a large number of Islamic religious texts, including the Quran.

“I assure you…I promise you…this was not intentional in any way. I offer my sincere apologies for any offense this may have caused, to the president of Afghanistan, the government of the Islamic Republic of Afghanistan, and most importantly, to the noble people of Afghanistan.”

The circumstances surrounding the incident are unclear. Unconfirmed reports suggest that NATO troops stationed at Bagram Air Base outside of Kabul attempted to dispose of a load of Qurans by setting them on fire, but were stopped by Afghan employees there.

Afghan protests against the destruction of the Muslim holy book have turned deadly in recent years. In April 2011, about 20 people were killed during several days of protests across Afghanistan after little-known U.S. pastor Terry Jones burned a Quran at his small Florida church.