Kiev and Tallin." Jewish sources said it is inconceivable that the office would have put up such a notice on its own initiative. Since It affects the residents in four different Soviet republics. they added. the announcement would have to be the result of a nationwide order by the Soviet Ministry of Internal Affairs. The Gagarinsky visa office is on the third floor of the district internal affairs office on Mosfllmskaya St. on the citys near southwest side. As of Friday night. there were no reports of the announcement having been posted in any of the citys other visa offices. which are believed to number between 15 and There have been widespread rumors here for months that Soviet authorities planned to purge the Olympic cities of "undesirable elements" during the summer in pursuit of their goal to turn the Games into a Socialist showcase. About 50 dissidents have been arrested during the last five months alone. and Nobel Prizewinning physicist Andrei D. Sakharov was exiled to Gorky. a city closed to foreign travel. in January.