ISLAMABAD — Pakistani troops killed 13 militants in the latest clashes in the Swat Valley, the army said today, underscoring the region’s fragile security even as refugees displaced by fighting return home.

One clash occurred near Kabal town, which lies across the river from Mingora, the Swat Valley’s main city. Kabal has been considered a likely hide-out of the Swat Taliban’s leadership.

Acting on a tip from residents, security forces raided a house in the town late Tuesday night where militants were believed to be hiding, said Sajjad Kasi, an army spokesman. The insurgents opened fire on the troops as they entered the building, and six militants were killed in the ensuing battle, Kasi said.

The military said in a statement that it had killed eight alleged insurgents, including two foreigners, in Kabal, while one soldier died in the exchange of fire. It was not possible to immediately reconcile the discrepancy in casualty numbers. The statement said five other suspected militants died in other clashes.

The Pakistani army says it has killed more than 1,700 militants since its latest offensive against the Taliban began in Swat more than two months ago. Despite ongoing reports of fighting, the army says that most of Swat is militant-free and that all the main urban centers are under army control.

It’s impossible to confirm the various death tolls independently because access to the area has been restricted, and the military has not provided figures on how many civilians have died.

More than 2 million residents of Swat and surrounding districts have fled their homes due to the offensive, according to the United Nations. A government repatriation program began Monday, and thousands of refugees have been heading back.

The program is supposed to focus first on the 200,000 or so refugees staying in relief camps and only certain zones in the valley are supposed to be open, but complications have arisen.

Some in the camps say they won’t go home until they are given promised financial assistance of around $300 per family. Others who have been staying elsewhere with relatives and friends have also begun to head back despite government requests that they wait until the camp residents go home, causing traffic jams at roadblocks. And some have gone to areas not yet technically open, including Mingora, where hundreds showed up Tuesday.

According to the government, 23,951 families are registered at relief camps in the northwest. Since Monday, at least 1,572 families from both relief camps and those staying elsewhere had returned to the valley. It was difficult to determine whether any families managed to get through using smaller, unmonitored routes.

Elsewhere in the northwest today, a roadside bomb exploded at a police checkpoint, killing a paramilitary soldier and a police officer and wounding six policemen, police official Imtiaz Khan said. No one claimed responsibility for the attack in the Bannu area, but Taliban fighters have often targeted security forces in the past.