Pakistan has demanded that the United States steeply reduce the number of Central Intelligence Agency operatives and Special Operations forces working in Pakistan, and that it halt C.I.A. drone strikes aimed at militants in northwest Pakistan. The request was a sign of the near collapse of cooperation between the two testy allies. Pakistani and American officials said in interviews that the demand that the United States scale back its presence was the immediate fallout from the arrest in Pakistan of Raymond A. Davis, a C.I.A. security officer who killed two men in January. In all, about 335 American personnel -- C.I.A. officers and contractors and Special Operations forces -- were being asked to leave the country, said a Pakistani official closely involved in the decision. It was not clear how many C.I.A. personnel that would leave behind; the total number in Pakistan has not been disclosed. But the cuts demanded by the Pakistanis amounted to 25 to 40 percent of United States Special Operations forces in the country, the officials said. The number also included the removal of all the American contractors used by the C.I.A. in Pakistan. In addition to the withdrawal of all C.I.A. contractors, Pakistan is demanding the removal of C.I.A. operatives involved in unilateral" assignments like Mr. Davis's that the Pakistani intelligence agency did not know about, the Pakistani official said.