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 during what he said was an attempt to rob him.
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.
The demands appeared severe enough to badly hamper American efforts — either through drone strikes or Pakistani military training — to combat militants who use Pakistan as a base to fight American forces in Afghanistan and plot terrorist attacks abroad.
The reductions were personally demanded by the chief of the Pakistani Army, Gen. Ashfaq Parvez Kayani, said Pakistani and American officials, who requested anonymity while discussing the delicate issue.
The scale of the Pakistani demands emerged as Lt. Gen. Ahmed Shuja Pasha, the head of Pakistan’s chief spy agency, the Inter-Services Intelligence Directorate, or the ISI, arrived in Washington on Monday for nearly four hours of meetings with the C.I.A. director, Leon E. Panetta, and Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff.
Two senior American officials said afterward that General Pasha did not make any specific requests for reductions of C.I.A. officers, contractors or American military personnel in Pakistan at the meetings.
“There were no ultimatums, no demands to withdraw tens or hundreds of Americans from Pakistan,” said one of the officials, who spoke on the condition of anonymity because of the tensions between the two spy services.
A C.I.A. spokesman, George Little, called the meetings “productive” and said the relationship between the two services “remains on solid footing.”
The meetings were part of an effort to repair the already tentative and distrustful relations between the spy agencies. Those ties plunged to a new low as a result of the Davis episode, which has further exposed the divergence in Pakistani and American interests as the endgame in Afghanistan draws closer.
The Pakistani Army firmly believes that Washington’s real aim in Pakistan is to strip the nation of its prized nuclear arsenal, which is now on a path to becoming the world’s fifth largest, said the Pakistani official closely involved in the decision on reducing the American presence.
On the American side, frustration has built over the Pakistani Army’s seeming inability to defeat a host of militant groups, including theTaliban and Al Qaeda, which have thrived in Pakistan’s tribal areas despite more than $1 billion in American assistance a year to the Pakistani military.
In a rare public rebuke, a White House report to Congress last week described the Pakistani efforts against the militants as disappointing.
At the time of his arrest, Mr. Davis was involved in a covert C.I.A. effort to penetrate one militant group, Lashkar-e-Taiba, which has ties to Pakistan’s military and intelligence establishment, has made deepening inroads in Afghanistan, and is perceived as a global threat.
The C.I.A. had demanded that Mr. Davis be freed immediately, on the grounds that he had diplomatic immunity. Instead, he was held for 47 days of detention and, the officials said, questioned for 14 days by ISI agents during his imprisonment in Lahore, infuriating American officials. He was finally freed after his victims’ families agreed to take some $2.3 million in compensation.
Another price, however, apparently is the list of reductions in American personnel demanded by General Kayani, according to the Pakistani and American officials. American officials said last year that the Pakistanis had allowed a maximum of 120 Special Operations troops in the country, most of them involved in training the paramilitary Frontier Corps in northwest Pakistan. The Americans had reached that quota, the Pakistani official said.
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.
An American official, who spoke on the condition of anonymity, said without elaborating that the Pakistanis had asked “for more visibility into some things” — presumably the nature of C.I.A. covert operations in the country — “and that request is being talked about.”
General Kayani has also told the Obama administration that its expanded drone campaign has gotten out of control, a Pakistani official said. Given the reluctance or inability of the Pakistani military to root out Qaeda and Taliban militants from the tribal areas, American officials have turned more and more to drone strikes, drastically increasing the number of attacks last year.
The drone campaign, which is immensely unpopular among the Pakistani public, had become the sole preserve of the United States, the Pakistani official said, since the Americans were no longer sharing intelligence on how they were choosing targets. The Americans have also extended the strikes to new parts of the tribal region, like the Khyber area near the city of Peshawar.
“Kayani would like the drones stopped,” said another Pakistani official who met with the military chief recently. “He believes they are used too frequently as a weapon of choice, rather than as a strategic weapon.” Short of that, General Kayani was demanding that the campaign return to its original, more limited, scope and remain focused narrowly on North Waziristan, the prime militant stronghold.
A drone attack last month, one day after Mr. Davis was released, hit Taliban fighters in North Waziristan, but also killed tribal leaders allied with the Pakistani military, infuriating General Kayani, who issued an unusually strong statement of condemnation afterward.
American officials defended the drone attack, saying it had achieved its goal of killing militants. But there have been no drone attacks since then.
General Kayani’s request to reduce the number of Special Operations troops by up to 40 percent would result in the closing of the training program begun last year at Warsak, close to Peshawar, an American official said.
Informed by American officials that the Special Operations training would end even with the partial reduction of 40 percent, General Kayani remained unmoved, the American official said.
American officials believed the training program was essential to improve the capacity of the nearly 150,000 Pakistani soldiers deployed to fight the Taliban in the tribal region.
The C.I.A. quietly withdrew all contractors after Mr. Davis’s arrest, the Pakistani official said.
Another category of American intelligence agents, declared operatives whose purpose was not clear, were also being asked to leave, the Pakistani official said.
In a sign of the severity of the breach between the C.I.A. and the ISI, the official said: “We’re telling the Americans: ‘You have to trust the ISI or you don’t. There is nothing in between.’ ”