Russia's FSB confirmed a US tip-off about a terror plot in Moscow after the US embassy warned of a "credible threat" of mass casualties at Tsaritsyno park on October 31.

The FSB said it had received the information about preparations for an attack in Moscow from the American side through partner channels and that work was under way, Kommersant reported on October 31. It gave no details of the plot or who was behind it.

The US embassy named the target in a security alert issued the same day. "The U.S. Embassy in Moscow is aware of a credible threat of a mass casualty event TODAY October 31, at the Tsaritsyno Museum Reserve in Moscow," it said. "The U.S. government is coordinating with appropriate Russian authorities on a response." It told Americans to avoid the area and crowds.

It is at least the third time US intelligence is known to have tipped off Moscow about a terror plot, and the second warning to come before a strike on a crowded Moscow venue in under three years. The last one, before the Crocus City Hall massacre in March 2024, was dismissed by the Kremlin and 149 people died. The exchange shows that Washington and Moscow still maintain a channel for passing on specific terror warnings despite the breakdown in wider security dialogue over the war in Ukraine.

Tsaritsyno, an 18th-century imperial palace and park complex in southern Moscow, is one of the city's busiest weekend attractions. The museum told the Telegram channel Mash it had no information about a threat and was operating as usual, but the park was evacuated on the evening of October 31, an organ concert in the grounds was stopped part-way through, and police and Rosgvardia vehicles gathered at the entrances, NSN reported. No attack or arrests had been reported by November 1.

Crocus ignored

The US embassy issued a similar alert on March 7, 2024, warning that extremists had "imminent plans to target large gatherings in Moscow, to include concerts", and US officials said the information had been passed to Russia's security services under Washington's "duty to warn" policy. Putin dismissed the Western warnings at an FSB board meeting on March 19 as "outright blackmail and an intention to intimidate and destabilise our society".

Three days later four gunmen opened fire on a rock concert at Crocus City Hall in Krasnogorsk, on the edge of Moscow, and set the building alight. The attack killed 149 people, the deadliest in Russia since the Beslan school siege in 2004, and was claimed by Islamic State's Afghanistan-based Khorasan branch (ISIS-K). FSB director Alexander Bortnikov later acknowledged the US warning but said it had been "general" in nature.

The four gunmen, all Tajik citizens, were arrested in the Bryansk region near the Ukrainian border, and Putin linked the attack to Ukraine, a claim Kyiv and Washington rejected. A Moscow military court jailed the four for life in March 2026.

An earlier tip-off worked. In December 2017 the CIA warned Russia of a plot by Islamic State supporters to bomb Kazan Cathedral in St Petersburg; the FSB detained seven suspects, and Putin phoned US President Donald Trump on December 17 to thank him.

Terror at home

Most of the worst attacks on Russia grew out of the two wars in Chechnya. Bombs that destroyed apartment blocks in Moscow, Buynaksk and Volgodonsk in September 1999 killed 307 people and were used to justify the second Chechen war; questions about the FSB's own role in them have never gone away. Chechen gunmen seized the Dubrovka theatre in Moscow during a performance of the musical "Nord-Ost" in October 2002, and some 130 hostages died, most of them from the gas special forces pumped in to end the siege. At Beslan in North Ossetia in September 2004, more than 330 people were killed, 186 of them children.

Suicide bombers from the North Caucasus insurgency then struck the Moscow metro in March 2010, killing 40, Domodedovo airport in January 2011, killing 37, and Volgograd twice in December 2013, killing 34. As the Chechen insurgency was crushed, mass-casualty attacks became rarer. The threat shifted to Islamic State recruits from Central Asia: a Kyrgyz-born bomber killed 14 passengers on the St Petersburg metro in April 2017, and the Crocus gunmen came from Tajikistan. The FSB said in May that it had foiled several plots this year with Tajik and Uzbek security services.

A partner in the war on terror

Putin has long pitched Russia to the West as a fellow victim of terrorism and a natural ally against it. He was the first foreign leader to call President George W Bush after the September 11 attacks in 2001. In his last speech in person to the UN General Assembly, in September 2015, he called for "a genuinely broad international coalition against terrorism" and said: "Similar to the anti-Hitler coalition, it could unite a broad range of parties willing to stand firm against those who, just like the Nazis, sow evil and hatred of humankind."

The coalition never materialised. Washington limited its contacts with the Russian military in Syria to avoiding clashes in the air, and after the full-scale invasion of Ukraine in 2022 any wider security dialogue ended. What remains is the US practice of passing on specific threats, which the FSB said it was acting on October 31.