The Pakistani army has started to interrogate the 18 al-Qaeda suspects it captured during Thursday's fiercely fought anti-terrorism operation on the Afghan border.
Eight suspected militants and two soldiers died in the operation
A Pakistani security official said the nationalities of the men were being checked but included Arabs and Chechens.
Eight al-Qaeda suspects were killed along with two Pakistani soldiers in the operation near Angor Adda in South Waziristan.
The operation was wrapped up on Friday on the eve of a visit by US Deputy Secretary of State Richard Armitage - he is expected in Islamabad on Saturday.
The security official said of those being interrogated: "It is a mixed bag. There are Chechens, Uzbeks, an Algerian and some Arab-speaking nationals. We are trying to determine their exact nationalities."
An official in Wana, the capital of the South Waziristan tribal region, told the Reuters news agency that Pakistani soldiers were conducting house-to-house searches around Angor Adda on Friday but that no new arrests had been made.
Thursday's operation represented one of the army's fiercest exchanges with al-Qaeda and Taleban fighters.
The rugged tribal area borders the Afghan province of Paktika, which has become a centre for ousted Taleban fighters.
Al-Qaeda chief Osama bin Laden and his deputy, Ayman al-Zawahri, are often reported to be hiding somewhere along the border.
Fighting continued throughout Thursday until nightfall, with helicopter gunships backing up hundreds of Pakistani troops who met stiff resistance.
The army began the operation "upon the receipt of credible intelligence about the presence of al-Qaeda elements", an army statement released on Thursday said.
Elite Quick Response Force troops surrounded a complex of six mud-walled compounds after a group of suspected militants was seen crossing back from
The troops fought for 14 hours with the militants, who returned grenades and machine-gun fire.
Military spokesman Major General Shaukat Sultan said the operation was launched because "these foreign elements were causing nuisance to the local
The tribal region of South Waziristan is a highly conservative area and the rugged tribesmen have traditionally supported the Taleban across the border.
The attack took place days after Mr Armitage criticised the commitment of some of the "rank and file" members of Pakistan's military in tackling al-Qaeda and the Taleban.
On his visit Mr Armitage will want to raise with President Pervez Musharraf the problem of militants travelling to and from Afghanistan.
The US envoy was due in Pakistan on Thursday but postponed because of illness.