MOSCOW, May 19 (JTA) — Russian police and security officials have defused a bomb discovered at the Shalom Jewish Theater in Moscow. The device, which was found Tuesday, contained more than one pound of explosives and a timing mechanism. Had it gone off it could have caused massive damage, police said. The bomb was found less than three weeks after two bombs went off near Moscow’s two largest synagogues. Police said there could be a link between the three events. Jewish community leaders reacted to the incident with renewed calls to tighten security in and around Jewish sites. An unusual set of circumstances led to the discovery of the explosive. One of the theater employees said she found a bag on May 10. Hoping that someone would come to pick it up, the employee said she took the bag out of the building and left it outside without checking its contents. Days later, a passer-by took the bag and left its contents — a cylinder-shaped device — at the theater’s entrance. On Tuesday night, an actor who needed to repair his car in front of the theater unscrewed the bolts on the device, which he thought might help him fix his car. The actor called the police, who with the help of Russia’s Federal Security Service bomb team, defused the device. The theater also rents space to several Jewish organizations, including the Va’ad, an umbrella group, and the Moscow Jewish Community House. In January, responding to a request from the Russian Jewish Congress, which is concerned about the rise in anti-Semitism, Russian police promised to provide special security measures for Jewish institutions in the Moscow area. Moscow Mayor Yuri Luzhkov promised that Jewish institutions in the Russian capital, including the four functioning synagogues, Jewish schools, Moscow’s Jewish theater and the office of a weekly Jewish newspaper, would be patrolled around the clock. Still, most institutions — the theater, for example — do not have any security at all. Jewish leaders hope that their security concerns will be addressed further now that Sergei Stepashin, who told a visiting delegation from the Anti-Defamation League two months ago that he was committed to fighting anti-Semitism, has taken the office of prime minister. Stepashin, who had been Russia’s interior minister, has had several contacts with the Jewish community in the past few years.