ISLAMABAD: Helicopter gunships destroyed a training camp for suicide bombers in northern Pakistan's troubled Swat Valley overnight, killing six Taliban militants, the army said Saturday.

Several more militants were wounded in the camp, located on a small island in the Swat River opposite the town of Charbagh, the army said. It said the operation followed reports on the camp by intelligence agents and local residents.

"The place was being used as a launching pad for preparing the suicide attackers," the army said in a statement, adding that those being trained were to bomb targets in Swat, including the valley's main city of Mingora.

About a week ago, two suicide attacks on consecutive days killed seven people in Swat.

Security forces have been winding down a nearly three-month offensive to dislodge the Taliban from the Swat Valley and surrounding areas, but sporadic clashes continue.

The United Nations said this past week that about 1.5 million people who had fled fighting in the wider region were returning home, and the World Health Organization said it was concerned about providing health support for them.

Authorities also have been battling militants in Pakistan's lawless and remote tribal belt along its northwestern border with Afghanistan.

Police were investigating the possible al-Qaida links of 12 suspected foreign militants arrested Friday on the edge of the tribal area, after they allegedly sneaked into the country from Iran, Punjab provincial police official Mohamad Rizwan said.

"One thing is certain, that they are terrorists," Rizwan said.

The men from Sudan, Russia, Turkey and Iran were arrested in the city of Dera Ghazi Khan, said Hassan Iqbal, a district official. Police also seized a laptop computer and $10,000 from the men, he said.

The detainees "had links with Taliban" and wanted to go to Pakistan's South Waziristan tribal region, Iqbal said, without giving further details.

South Waziristan is a stronghold of former Pakistani Taliban commander Baitullah Mehsud, who was killed by a CIA missile strike earlier this month.

Pakistan has deployed more than 100,000 troops in the tribal regions since the Sept. 11, 2001, attacks in the United States. Authorities have arrested about 1,000 Taliban and al-Qaida suspects over the past few years, including senior aides to al-Qaida chief Osama bin Laden and his deputy, Ayman al-Zawahri.

Al-Zawahri, in a video posted Thursday on Islamic militant Web sites, said a Pakistani offensive against the Taliban in the Swat Valley was doomed to fail. He urged Pakistanis to "back the jihad (holy war) and mujahedeen" with fighters, money and support.