At least five people have been killed in Pakistan's South Waziristan region in suspected US drone attacks on alleged hideouts of anti-government fighters.

Officials said that at least three missiles were fired on Thursday in two separate areas in the region known as a stronghold of al-Qaeda and Taliban fighters.

"Three missiles struck a training camp run by a local militant commander, Malang Wazir," an intelligence official, who asked not to be identified, said.

Another security official, citing witnesses, said five people had been killed in the same strike.

The second attack was in a separate village but neither of the officials had details of any casualties.

Swat offensive

Frequent attacks by pilotless US drone aircraft have been heavily criticised by Pakistani leaders for killing innocent bystanders and infringing upon national sovereignty.

South Waziristan is part of the federally administered tribal areas which border the North West Frontier Province (NWFP).

The NWFP contains the Swat valley where hundreds of thousands of civilians have fled a government offensive against the Taliban.

The Pakistani military has also been softening up targets in South Waziristan and is expected to launch an offensive against Taliban fighters in the region.