KABUL, Afghanistan (AP) -- A gunman killed two American advisers inside a heavily guarded government compound in Kabul Saturday, officials said, as protests against the burning of copies of the Muslim holy book roiled the country for a fifth day.
U.S. officials said the assailant remained at large as neither an apology from President Barack Obama nor gunfire from Afghan police could quench public outrage over what NATO insisted was an inadvertent desecration of the Quran.
Two Afghan officials said the ministry shooting did not involve any Afghans. They spoke anonymously to discuss a NATO incident. One of the officials noted that the shooting occurred inside a secure room at the ministry that Afghan staff do not have access to.
NATO confirmed that two service members were killed, but spokesman Lt. Col Jimmie Cummings said "initial reports say it was not a Western shooter." He declined to provide further information.
A U.S. official in Washington confirmed that the two killed were American. The official spoke anonymously to discuss information that had not been publicly released.
"The assailant is unknown, and an aggressive search is under way to determine who is responsible," Pentagon press secretary George Little said.
NATO forces have advisers embedded in many Afghan ministries, both as trainers and to help manage the transition to Afghan control and foreign forces prepare to withdraw by the end of 2014. The Afghan Interior Ministry oversees all of the country's police, so has numerous NATO advisers.
Saturday's attack comes as tensions between the Afghans and the Americans are high following the burning of copies of the Muslim holy book at a U.S. base that sparked days of deadly protests
In a statement, Taliban spokesman Zabiullah Mujahid said the gunman was an insurgent named Abdul Rahman. He said an accomplice inside the ministry helped him get inside the compound. He said the killings were a planned response to the Quran burnings.
"After the attack, Rahman informed us by telephone that he was able to kill four high-ranking American advisers," Mujahid said. The Taliban frequently exaggerate casualty claims.
At least 25 people have been killed and hundreds wounded since Tuesday, when it first emerged that Qurans and other religious materials had been thrown into a fire pit used to burn garbage at Bagram Air Field, a large U.S. base north of Kabul.
Among those dead were two U.S. soldiers who were killed by one of their Afghan counterparts while a riot raged outside their base.
President Barack Obama and other U.S. officials apologized and said the burning of Qurans was a terrible mistake, but the incident has sent thousands to the streets in this deeply religious country.
In Kunduz, the capital of Kunduz province in northeast Afghanistan, more than 1,000 protesters demonstrated. At first they were peaceful, but as the protest continued they began throwing stones at government buildings and a U.N. office, said Sarwer Hussaini, a spokesman for the provincial police. He said the police were firing into the air to try to disperse the crowd.
The U.N. confirmed in a statement that its Kunduz compound was attacked, but said all its staff in Kunduz and in the country were unhurt and accounted for. The statement thanked Afghan security forces for their quick response to the assault.
Associated Press writer Robert Burns in Washington contributed to this report.