The new commander of NATO forces in Afghanistan says he is concerned about violence spilling into the country from Pakistan's tribal regions.

General David McKiernan told reporters in Kabul Wednesday 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 militants has given militants more leeway to carry out operations in Afghanistan.

Separately, the U.S.-led coalition says two of its soldiers were killed when their helicopter crashed Thursday in southern Afghanistan.

In a statement, the coalition says the helicopter had been on a routine maintenance mission when it crashed in Kandahar province. Officials say there was no report of hostile activity related to the incident.

Also Thursday, Afghan officials say coalition forces have fought off an attack in southern Afghanistan, killing nine Taliban militants.

Zabul province deputy police chief Faridullah Khan says the militants attacked a U.S.-Afghan convoy, leading to a firefight.

Khan says in a separate incident, another patrol was attacked by a suicide bomber. Two civilians were wounded.

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