Pakistani forces captured 40 militants in the South Waziristan region on the Afghan border, a military spokesman said yesterday, a day after up to 90 rebels were killed in two battles.

Fighting has intensified in recent days between government forces and Al-Qaeda-linked militants led by a commander the government and the CIA say was behind the assassination of opposition leader Benazir Bhutto last month.

"Last night, during the operation at Chaghmalai, we captured 40 miscreants... the complete Chaghmalai area is cleared of militants," said military spokesman Major-General Athar Abbas.

A wave of violence including a barrage of suicide bombs in recent months has raised fears about stability in nuclear-armed Pakistan, which is a major ally of the United States in its campaign against terrorism.

The assassination of two-time prime minister Bhutto in a gun and bomb attack in Rawalpindi on December 27 compounded that worry.

Militants ambushed a convoy in the Chaghmalai area of South Waziristan on Friday and 20 to 30 of them were killed when security forces fought back, Abbas said, citing estimates reported by observation posts.