Fourteen suspected al-Qaeda militants, most of them Arabs, have been arrested in Pakistan and others are under strict surveillance.
The arrests were made on Wednesday night in the northwestern city of Peshawar near the Afghan border, a Pakistani interior ministry official said.
"They are Sudanese, Algerians and Egyptians and a few others," he said. "We are interrogating them and will decide their future accordingly."
The English-language newspaper Dawnsaid agents of the US Federal Bureau of Investigation took part in the arrests and the suspects were now in US hands.
"The detainees were immediately handed over to the American officials who took them to an undisclosed destination for interrogation," the paper said.
Pakistani military ruler General Pervez Musharraf said this week small bands of al-Qaeda militants could have crossed into the country from Afghanistan and vowed to do his utmost to track them down with US help.
US officials said last month a small number of special operations forces were in Pakistan pursuing remnants of Afghanistan's former ruling Taliban movement and al-Qaeda militants.
A police spokesman in Karachi said some suspected al-Qaeda members had been living in Pakistan's urban areas and they were being closely watched.
He said most of them were living in Afghan refugee camps on the outskirts of Karachi.