LAHORE - Authorities will keep the American and Western diplomats under strict surveillance to prevent them from going to places they are not authorised to, knowledgeable sources say. Checks on their movements have been enhanced following the release of Raymond Davis, a CIA contractor who killed two innocent citizens in the metropolis in January, an episode that fuelled anti-Americanism in the country. The CIA-led May 2 Abbottabad operation, carried out without the knowledge of the Pakistan government, in which Osama bin Laden was killed, widened the gulf between the two allies in the war on terror. According to sources, the security agencies have written a letter to the Foreign Office requiring it to inform them about the places a US diplomat(s) had been allowed to go to perform his/her official duties. The diplomats would not be allowed to go beyond the mandated venues. It is because of the changed policy that the US diplomats who were going to Peshawar from Islamabad without clearance from the Foreign Office were sent back to the federal capital by the relevant authorities on Wednesday and on several other occasions. It is said that Raymond Davis was one of the six CIA operatives based in the Punjab the metropolis. However, now there is only one left, four of them were withdrawn following a decision of the federal government to expel more than 100 American trainers based at various places. The governments latest decision to issue visas to 87 CIA operatives as a result of recent talks between the ISI chief and CIA officials in Washington means that the spying network would expand again in the days ahead. Since most of the operatives reportedly land in Lahore because of three direct flights from New York every week, the security agencies have increased their presence here to keep a watchful eye on the newcomers and their activities. According to sources, diplomats from all western countries are also being tracked very regularly. It is said that during the first week of the current month, many US and British diplomats visited Lahore and met with various people they were not authorised to.