 More countries warn about terrorism in Russia after Moscow plot thwarted. More countries have joined the United States in warning their citizens in Russia to avoid crowds over an imminent terrorist threat shortly after Russian officials said they thwarted an attempted attack on a Moscow synagogue, according to Newsweek. A security alert issued warned that the U.S. Embassy in Moscow was monitoring reports that extremists have imminent plans to target large gatherings in Moscow to include concerts and U.S. citizens should be advised to avoid large gatherings. The British Embassy in Moscow quickly shared the warnings while advising U.K. nationals to avoid all travel to Russia. At least six other nations had joined in warning their citizens about the alleged threat including Canada, Germany, Sweden, South Korea, Latvia and the Czech Republic. While the nature of the threat was nonspecific, Russia's Federal Security Service said in a statement that it had prevented an attempt by an Islamic state terror cell to commit a terrorist act against one of the Jewish religious institutions in Moscow according to Russian state media agency TAS. Active search measures established that they were militants of an international terrorist organization preparing an attack on the congregation of a synagogue with the use of firearms, the FSB statement reads. During an operation to detain them, the terrorists put up armed resistance to Russian FSB staff and as a result were neutralized by return fire. It continues. It was unclear whether or not the purported synagogue attack plan was tied to the threat that the U.S. Embassy claimed soon after. The U.S. State Department spokesperson told Newsweek that there was no higher priority than the safety and security of U.S. citizens overseas, but declined comment on any potential connection pointing out the department's policy of avoiding the disclosure of information on intelligence matters.