The US embassy in Russia issued a warning on Friday (March 8) stating that "extremists" had imminent plans to target large public gatherings in Moscow.
This came hours after Russian security services claimed to have foiled a planned shooting at a synagogue by a cell of the militant Sunni Muslim group Islamic State.
The embassy gave no further details about the nature of the threat, however, stated that people should avoid concerts and crowds and be vigilant.
"The Embassy is monitoring reports that extremists have imminent plans to target large gatherings in Moscow, including concerts, and U.S. citizens should be advised to avoid large gatherings over the next 48 hours," the embassy said on its website.
The Federal Security Service (FSB) said that an Islamic State cell was operating in Russia's Kaluga region as part of the Afghan arm of the group.
The cell "was preparing to attack the congregants of a synagogue using firearms," the FSB said.
It then said that when Russian special forces confronted the terrorists, they offered resistance and were "neutralized" by retaliatory fire.
"Firearms, ammunition, as well as components for the manufacture of an improvised explosive device were found and seized," the FSB further said.
Russia's war against Ukraine has triggered a crisis in Moscow's relation with the West, which is at its worst since the 1962 Cuban Missile Crisis.
The Kremlin has accused the United States of fighting against Russia by providing financial, military, and intelligence support to Ukraine.
The US embassy in Russia has also repeatedly urged American citizens to leave the country on an immediate basis.
US embassy warns of imminent plans of attack by '''extremists''' in Moscow - World News