Military officials in Pakistan say they have killed eight suspected al-Qaida militants and have arrested another 18 in what is being described as the largest-ever operation against the international terrorist network.

Hundreds of Pakistani troops, backed by Cobra helicopters, conducted the anti-al-Qaida operation on Thursday in a rugged tribal region, Angor Adda. The area is close to the border with Afghanistan.

Senior military officials leading the offensive say the suspected terrorists were heavily armed and put up "stiff resistance."

Pakistan Army spokesman, Major-General Shaukat Sultan, tells VOA the nearly 16-hour operation has ended and was a complete success. He says the Army launched the offensive after the al-Qaida suspects refused to surrender.

"At the end of the operation the casualties were eight dead from the terrorists and 18 captured alive, out of whom three were wounded," he said. "[And our] own troops suffered four casualties, two dead and two wounded. The area was absolutely cleared and there are no more terrorists in the area."

Authorities are questioning the detained al-Qaida suspects. Several foreign nationals are believed among the detainees, but the Army spokesman refused to disclose their nationalities.

"They are being interrogated and I would not consider it appropriate to give out their identities," said General Sultan.

Reporters on the scene say many of the dead and prisoners appeared to be Arab nationals.

Pakistani soldiers seized a large quantity of arms and ammunition from one of the houses they raided. Senior military officials say the suspected terrorists could have been involved in recent attacks on the U.S.-led anti-terrorism forces on the Afghan side of the border.

Officials in Afghanistan have long accused Pakistan of not doing enough to stop Islamic militants crossing from Pakistani border regions to attack U.S. and Afghan targets. Pakistani military officials say the operation in Angor Adda shows the country's commitment to eliminate terrorism in all its forms from Pakistan.