Pak troops backed by helicopter gunships yesterday launched a new operation to capture al-Qaeda suspects in a remote tribal district near the Afghan border.

However, Information Minister Sheikh Rashid Ahmed did not confirm whether any arrests have been made.

The operation to capture "foreign terrorists" started early morning west of Wana, the capital of South Waziristan tribal area, military spokesman Major General Shaukat Sultan told AFP.

"The operation is progressing," Sultan said five hours after the army went into action.

The number of troops involved in the operation and other details were not immediately available.

"We don't yet have details about casualties or arrests," he added.

South Waziristan is one of the main suspected hideouts for Osama bin Laden and other top al-Qaeda fugitives. Officials in the region have said American planes dropped leaflets in the area on Wednesday urging residents to cooperate with authorities and turn in any foreign terrorists.

It was at least the second major operation in South Waziristan in recent months.

In October last year Pakistani troops conducted a major operation in South Waziristan territory, killing eight al-Qaeda suspects and arresting 18. Two Pakistani soldiers were also killed in a gunbattle with the suspects.

Local officials said the operation was taking place at Kalu Shah, around 40km from the porous border with Afghanistan.

"Helicopters are hovering over the area and firing at targets," a local official said.

South Waziristan is located opposite the eastern Afghan province of Paktika and has long been a suspected sanctuary for al-Qaeda and resurgent Taliban fighters fleeing US-led forces in Afghanistan.

Wana is around 330km southwest of the capital Islamabad.

US troops have frequently chased suspected Taliban attackers to the border, only to see them slip through the unmarked frontier into Pakistan's semi-autonomous tribal areas.

The target of that raid was apparently Said al-Kadr, an Egyptian-born Canadian citizen. Pakistani officials say he appears to have escaped, but his family has said he is missing and has accused the Pakistani government of hiding information about his fate.

Pakistan is a key US ally and has turned over more than 500 al-Qaida suspects, including alleged No. 3 Khalid Shaikh Mohammed, who was captured in March.