Afghan villagers told a public health official Monday that a NATO airstrike killed six civilians in a mountainous region of eastern Afghanistan, but the military alliance said four to eight militants were killed. Thirty others died in a spate of violence around the country.

Four people were wounded in the airstrike, including one woman, and had been taken to a hospital in Asadabad, the capital of Kunar province, said Asadullah Fazli, Kunar's chief of public health.

Fazli said that villagers from Wata Pur district told him that six civilians died during the airstrike, and that three houses were destroyed.

NATO's International Security Assistance Force said that "four to eight" enemy fighters were killed and that intelligence intercepts indicated "the hostile intent of the enemy to attack ISAF posts." Still, a spokesman said it was possible civilians were wounded.

"We deeply regret any possible civilian injuries caused by our operations against the enemy," said Captain Mark Durkin, ISAF's spokesman. "We will thoroughly investigate the allegations of civilian injuries and, if found true, provide assistance to support the law-abiding people affected."

Civilian deaths caused by U.S. or NATO forces have long been a sore point for Afghan President Hamid Karzai, who has pleaded with international forces to reduce the number of innocent Afghans killed in operations.

Because of the remote and dangerous regions most operations happen in, it is almost impossible for journalists and human rights workers to verify villager claims. Taliban fighters have been known to coerce Afghans into falsely claiming that civilians were killed, but the U.S. has also been slow to acknowledge when its operations kill innocent Afghans.

The latest allegation of civilian deaths comes less than a week after the U.S. military admitted that a mission in Khost province killed five civilians, including two females and an infant.

Thirty other people were killed around the country in military operations and roadside bombs, officials said. Among the biggest incidents:

— U.S. airstrikes killed seven militants in Wardak province after they attacked an American patrol on Saturday, the U.S. military said. There were no American casualties in the clash, which happened in Sayed Abad district, it said.

— Afghan and international forces killed nine militants Sunday in a gun battle in Uruzgan province, the Ministry of Defense said.

— A roadside bomb killed four Afghan civilians Monday in Herat, the Ministry of Interior said.

The spike in violence comes as the United States prepares to send 21,000 more troops to Afghanistan. President Barack Obama ordered the troop deployments to help fight a resurgent Taliban insurgency.

There are currently roughly 70,000 international forces in Afghanistan, including a record 38,000 Americans.