Pakistan's military says it has killed more than 60 suspected fighters close to the country's border with Afghanistan.

Fighter jets and ground forces attacked targets in the Orakzai tribal region in the latest attempt to flush out Pakistani Taliban fighters from the area.

Up to 42 people died in Monday's air raids, with a further 18 killed by Pakistani troops in the ground.

One soldier died and 10 were wounded in the fighting, the country's military said.

The campaign against Pakistani Taliban fighters in Orakzai is now in its second month.

Thousands of people have fled the area because of the heavy fighting, and media access is restricted, making it impossible to verify the military's claims.

Meanwhile, fighters who kidnapped 60 people at gunpoint elsewhere in Pakistan's tribal region on Sunday have released 40 of their hostages, according to a local official.

A further 10 people said they escaped from the kidnappers, who ambushed the group in Kurram while they were on their way to Peshawar, Rasheed Khan, a local administrator, said.

The kidnappers released women, children and the poor, but kept wealthy hostages so they could declare ransom from their families, Khan said.

"Now the militants only have 10 people in their custody, and efforts are under way to recover them,'' he said.