http://www.washingtonpost.com/wp-dyn/content/article/2011/02/23/AR2011022305040.html ISLAMABAD, Pakistan -- Pakistan's ISI spy agency is ready to split with the CIA because of frustration over what it calls heavy-handed pressure and its anger over what it believes is a covert U.S. operation involving hundreds of contract spies, according to an internal document obtained by The Associated Press and interviews with U.S. and Pakistani officials. Such a move could seriously damage the U.S war effort in Afghanistan, limit a program targeting al-Qaida insurgents along the Pakistan frontier, and restrict Washington's access to information in the nuclear-armed country. According to a statement drafted by the ISI, supported by interviews with officials, an already-fragile relationship between the two agencies collapsed following the shooting death of two Pakistanis by Raymond Davis, a U.S. contracted spy who is in jail in Pakistan facing possible multiple murder charges. "Post-incident conduct of the CIA has virtually put the partnership into question," said a media statement prepared by the ISI but never released. A copy was obtained this week by the AP. The statement accused the CIA of using pressure tactics to free Davis. "It is hard to predict if the relationship will ever reach the level at which it was prior to the Davis episode," the statement said. "The onus of not stalling this relationship between the two agencies now squarely lies on the CIA." The ISI fears there are hundreds of CIA contracted spies operating in Pakistan without the knowledge of either the Pakistan government or the intelligence agency, a senior Pakistani intelligence official told the AP in an interview. He spoke only on condition he not be identified on grounds that exposure would compromise his security Pakistan intelligence had no idea who Davis was or what he was doing when he was arrested, the official said, adding that there are concerns about "how many more Raymond Davises are out there." Davis was arrested Jan. 27 in Lahore after shooting two Pakistanis. A third Pakistani was killed by a U.S. Consulate vehicle coming to assist the American. Pakistan demanded the driver be handed over, but the AP has learned the two U.S. employees in the car now are in the United States. Davis has pleaded self-defense, but the Lahore police upon completing their investigation said they would seek murder charges. The ISI official told the AP that Davis had contacts in the tribal regions and knew both the men he shot. He said the ISI is investigating the possibility that the encounter on the streets of Lahore stemmed from a meeting or from threats to Davis. U.S. officials deny Davis had prior contact with the men before the incident, and CIA spokesman George Little said any problems between the two agencies will be sorted out. "The CIA works closely with our Pakistani counterparts on a wide range of security challenges, including our common fight against al-Qaida and its terrorist allies," he said. "The agency's ties to ISI have been strong over the years, and when there are issues to sort out, we work through them. That's the sign of a healthy partnership." The CIA repeatedly has tried to penetrate the ISI and learn more about Pakistan's nuclear program. The ISI has mounted its own operations to gather intelligence on the CIA's counterterrorism activities The ISI is now scouring thousands of visas issued to U.S. employees in Pakistan. The ISI official said Davis' visa application contains bogus references and phone numbers. He said thousands of visas were issued to U.S. Embassy employees over the past five months following a government directive to the Pakistan Embassy in Washington to issue visas without the usual vetting by the interior ministry and the ISI. The same directive was issued to the Pakistan embassies in Britain and the United Arab Emirates, he said. Within two days of receiving that directive, the Pakistani Embassy issued 400 visas and since then thousands more have been issued, said the ISI official. A Western diplomat in Pakistan agreed that a "floodgate" opened for U.S. Embassy employees requesting Pakistani visas. The ISI official said his agency knows and works with "the bona fide CIA people in Pakistan" but is upset that the CIA would send others over behind its back. For now, he said, his agency is not talking with the CIA at any level, including the most senior. To regain support and assistance, he said, "they have to start showing respect, not belittling us, not being belligerent to us, not treating us like we are their lackeys." NATO and U.S. operations in Afghanistan could be adversely effected by a split between the ISI and the CIA. Washington complains bitterly about Pakistan's refusal to go after the Pakistani-headquartered Haqqani network, which is believed to be the strongest fighting force in Afghanistan and closely allied with al-Qaida. The ISI official said Pakistan is fed up with Washington's complaints, and he accused the CIA of planting stories about ISI assistance to the Haqqani network. Relations between the CIA and ISI have been on a downward slide since the name of the U.S. agency's station chief in Pakistan was leaked in a lawsuit accusing him of killing civilians in a drone strike. Fearing for his safety, the CIA eventually pulled the station chief out of the country. ISI leaders balked at allegations that they outed the CIA top spy in their country. Former and current U..S. officials believe the station chief fell out of favor, but the Pakistanis say this is not the case Those accusations and the naming of ISI chief Shujah Pasha in a civil lawsuit in the United States - filed by family members of victims of a November 2008 attack in Mumbai, India, by insurgents - started the downslide in relations, the ISI official said. To help repair the crucial relationship, the CIA earlier this year dispatched a very senior officer to be the new station chief who was previously the head of the European Division, one of the most important jobs in the National Clandestine Service, the agency's spy arm. The spy agencies have overcome lows before. During President George W. Bush's first term, the ISI became enraged after it shared intelligence with the United States, only to learn that the then-CIA station chief passed that information to the British. The incident caused a serious row, one that threatened the CIA's relationship with the ISI and deepened the levels of distrust between the two sides. At the time Pakistan almost threw the CIA station chief out of the country.