Pakistani military officials say troops have arrested 100 suspected al-Qaida members in an operation in remote northwestern Pakistan.
Pakistani General Safdar Hussein says some foreign fighters are among those captured. But it is not yet clear whether any high ranking al-Qaida officials have been detained.
Pakistani forces have been pounding a region near the Afghan border for days.
Earlier reports suggested that Ayman al-Zawahiri, a senior aide to al-Qaida leader Osama bin Laden, may be hiding in the area. But General Hussein says he now believes the militants may include a senior Chechen or Uzbek leader -- rather than al-Zawahiri.
He said most radio intercepts of messages from the region have been in the Chechen or Uzbek languages.
Thirteen civilians were killed Saturday when their vehicles were hit by rocket fire in the area. The Pakisani military blames militants, but some local reports say an army helicopter fired on the cars.
Pakistani officials say several hundred foreign fighters and local tribesmen are believed to be hiding in heavily fortified compounds in a mountainous region in South Waziristan.
Information for this report is provided by AFP and Reuters.