Seven insurgents were killed in a military operation near where militants this week breached a U.S. outpost in eastern Afghanistan, the Afghan Defense Ministry said Tuesday.

Separately, Afghan troops killed 12 insurgents west of the capital, Kabul, the ministry said in a statement.

The Taliban-led rebellion appears to be intensifying despite the largest presence of foreign forces in Afghanistan since the U.S.-led invasion that ousted the hard-line regime in 2001.

More than 2,500 people — mostly militants — have reportedly died in insurgency-related violence this year, according to an Associated Press tally of figures from Afghan and Western officials.

In the eastern operation Monday, troops killed seven insurgents and nabbed an "Arab terrorist" in the area of Wanat village in Nuristan province where nine American soldiers died in a militant attack over the weekend, the Defense Ministry said.

Its statement gave no further details and did not say whether foreign forces supported the Afghan army. NATO and U.S. military officials were not immediately available for comment.

U.S. troops, meanwhile, disarmed the district police force and briefly detained the district chief and police chief for questioning at the U.S. base, said Omar Sameh, a spokesman for district chief. Both were released within 24 hours, he said. Sameh did not say what the chiefs were questioned about.

Sunday's assault was the deadliest against the U.S. military in three years and deepened doubts about its ability to contain Islamic militants and keep locals on their side, amid reports that residents had advance knowledge of the attack and some local tribesmen joined the assault.

Some 200 militants with machine guns, rocket-propelled grenades and mortars attacked the U.S. outpost in Wanat, just three days after it was established near the Pakistan border.

An unknown number of militants got inside the outpost but were beaten back after hours of fighting.

Cooperation in the war on terror among Pakistan, Afghanistan and U.S. and NATO forces has been strained by accusations that Taliban, al-Qaida and other militants enjoy sanctuary on Pakistani soil.

Afghanistan on Monday alleged Pakistan's intelligence service and army are behind the bloody Taliban-led insurgency, calling its security forces the "world's biggest producers of terrorism and extremism."

Pakistan rejected the allegations Tuesday and accused Afghanistan of causing an "artificial crisis" in relations.

Meanwhile, Afghan troops clashed with militants in central Wardak province on Monday, leaving 12 militants dead and four Afghan soldiers wounded, the Defense Ministry said.

The militants were suspected of planting roadside bombs in a recent spate of attacks on the main highway passing through the province, the ministry said.