A further 19 fighters were captured in Wednesday's fighting in the Shawal area of North Waziristan, said Major General Shaukat Sultan, the spokesman.

Eight fighters and four soldiers were killed late on Tuesday after fighters attacked a military base in Mana, about 50km (30 miles) west of the main town of Miranshah.

Eight more fighters died in clashes on Wednesday, Sultan said.

"Helicopter gunships have been flying in and out of Miranshah towards Shawal since morning," a resident of Miranshah said.

Intelligence officials said three soldiers were injured in a separate overnight attack in the nearby Datta Kheil area.

On Monday, five people were killed by an exploding landmine and two fighters died in a clash with security forces in the same area.

Military officials have said Arab, Central Asian and Afghan fighters are present in the region, and that local tribesmen are showing increasing resistance to the government in the lawless region

Tensions have been running high in North Waziristan since 200 tribesmen and fighters were killed in clashes last month with Pakistani security forces.