"Die, die, foreigners!" the demonstrators shouted. Some fired rifles into the air. Others threw rocks at the gate of the base and set tires ablaze.

The burning of the Quran and other religious books was unintentional, said U.S. Gen. John Allen, the top commander of American and NATO forces in Afghanistan.

The incident stoked anti-foreign sentiment that already is on the rise after a decade of war in Afghanistan and fueled the arguments of Afghans who claim foreign troops are not respectful of their culture or Islamic religion.

Early Tuesday, as word of the incident spread, about 100 demonstrators gathered outside the sprawling Bagram Air Field in Parwan province. As the crowd grew, so did the outrage.

One protester, Mohammad Hakim, said if U.S. forces can’t bring peace to Afghanistan, they should go home.

"They should leave Afghanistan rather than disrespecting our religion, our faith," Hakim said. "They have to leave and if next time they disrespect our religion, we will defend our holy Quran, religion and faith until the last drop of blood has left in our body."

Ahmad Zaki Zahed, chief of the provincial council, said U.S. military officials took him to a burn pit on the base where 60 to 70 books, including Qurans, were recovered. The books were used by detainees once incarcerated at the base, he said.

"Some were all burned. Some were half-burned," Zahed said, adding that he did not know exactly how many Qurans had been burned.

Zahed said five Afghans working at the pit told him that the religious books were in the garbage that two soldiers with the U.S.-led coalition transported to the pit in a truck late Monday night. When they realized the books were in the trash, the laborers quickly worked to recover them, he said.

"The laborers there showed me how their fingers were burned when they took the books out of the fire," he said.

In a statement, Allen said he had ordered an investigation and offered his apologies to the president and people of Afghanistan. He thanked local Afghan workers "who helped us identify the error, and who worked with us to immediately take corrective action."

"We are thoroughly investigating the incident and are taking steps to ensure this does not ever happen again," Allen said. "I assure you, I promise you, this was not intentional in any way."

Afghan Army Gen. Abdul Jalil Rahimi, the commander of a military coordination office in the province, said he and other officials met with protesters, tribal elders and clerics to try to calm their emotional response. "The protesters were very angry and didn’t want to end their protest," he said.

Later, however, the protesters ended the rally and said they would send 20 representatives from the group to Kabul to talk with Afghan parliamentarians and demanded a meeting with President Hamid Karzai, Rahimi said.

The governor’s office in Kandahar province in southern Afghanistan called the incident a "shameful move by some stupid individuals."

Zia Ul Rahman, deputy provincial police chief, said between 2,000 and 2,500 protesters demonstrated at the base.

"The people are very angry. The mood is very negative," Rahman said while the rally was going on. "Some are firing hunting guns in the air, but there have been no casualties."

Police said a similar protest on Tuesday just east of Kabul ended peacefully.

In April 2011, Afghans protesting the burning of a Quran by a Florida pastor turned deadly when gunmen in the crowd stormed a U.N. compound in the northern city of Mazar-e-Sharif and killed three staffers and four Nepalese guards.

Separately, officials in Helmand province in the south said insurgents beheaded four people Sunday night in Washer district on the charge that they were spies.

"The militants told the local people that they were guilty because they were carrying satellite phones," provincial spokesman Daoud Ahmadi said.

Taliban spokesman Qari Yousef Ahmadi said that the militant group was not involved in the killings.

Also in the south, a NATO service member died Tuesday as a result of a non-battle related injury. The U.S. led coalition gave no further details about the death. So far this year, 44 NATO service members have been killed in Afghanistan.