US soldiers block a road as they stand guard at the site of a suicide attack in Kabul, 29 May 2008 (file photo)

Afghan officials say a U.S.-led coalition airstrike has killed 32 militants in southeastern Afghanistan.

A spokesman for the governor of Paktika province said Friday the strike occurred on Thursday in Paktika, which borders Pakistan.

Coalition officials confirmed the attack and said they had reports of 20 militants killed in the operation.

Also Thursday, coalition officials said NATO forces fought off an attack by militants in southern Zabul province.  At least nine militants were killed.

In a separate incident in the same province, a suicide bomber attacked a patrol, wounding two civilians.

The new commander of NATO forces in Afghanistan expressed concern about violence spilling into the country from Pakistan's tribal regions.

Earlier this week in Kabul, General David McKiernan said he wants to stem the flow of militants into Afghanistan, and that he hopes to develop a close relationship with his Pakistani counterparts.

Other U.S. officials have also expressed concern about security along the border.

They say the Pakistani government's pursuit of peace talks with pro-Taliban and al-Qaida-linked groups has given militants more leeway to carry out operations across the border.

Some information for this report was provided by AFP, AP and Reuters.