The U.S. Embassy in Moscow issued a security alert Saturday warning people of a potential "mass casualty event" at the 2 Museum Reserve in Moscow.

"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 at Dolskaya Ulitsa 1, Moscow, Russia 11569. The U.S. government is coordinating with appropriate Russian authorities on a response," the embassy wrote in a statement.

The alert warned people to avoid the Tsaritsyno Museum area and to "stay alert, and avoid crowds."

Founded in 1775 as a summer home for Russia's Catherine II, the Tsaritsyno Museum is now a popular tourist attraction in Russia's capital.

INSIDE MELANIA TRUMP'S SECRET DIPLOMATIC ROLE IN THE RUSSIA-UKRAINE CEASEFIRE DEAL

The museum itself attracted more than 2 million visitors in 2022, Moscow's deputy mayor, Natalya Sergunina, said in 2023. The surrounding grounds, enjoyed by Moscow's local citizens for physical activity and dog walking, get even more foot traffic, according to The Art Newspaper.

The U.S. Embassy's alert also included a warning to people in the Moscow area to keep cellphone batteries and other batteries charged, remain aware of surroundings and review a personal security plan.

The alert was issued as tensions in the ongoing war between Russia and Ukraine continue to escalate.

TRUMP ANNOUNCES IMMEDIATE ENERGY CEASEFIRE BETWEEN RUSSIA AND UKRAINE

On Friday, Ukraine struck an oil refinery in southern Russia, ending a two-week pause on energy infrastructure attacks brokered by President Donald Trump between the warring nations.

The previous day, Russian drone and missile strikes in Ukraine killed at least 27 civilians, according to The Wall Street Journal.

Fox News Digital contacted the U.S. Embassy in Moscow for further information.

CLICK HERE TO DOWNLOAD THE FOX NEWS APP

This is a developing story. Please check back for updates.

The Court of Arbitration for Sport (CAS) ruled on Friday that Russian teams can compete in next year's men's and women's world championships, overturning the International Ice Hockey Federation (IIHF)'s decisions to exclude them from its competitions.

The IIHF has excluded Russia, which has won ​five IIHF world titles as an independent nation, from most international ice hockey competitions since 2022 following the country's invasion of Ukraine.

Russia did not compete in Olympic hockey earlier this year, the first since 2014 which had NHL players, nor was it included in the NHL's 4 Nations Face-Off. Russia invaded Ukraine on Feb. 24, 2022, four days after Olympic competition ended that year.

CLICK HERE FOR MORE OUTKICK SPORTS COVERAGE

The decision was not met with a warm reception from the IIHF and several other countries, including Canada, which will host the World Junior Championships later this year.

"Canada maintains, as it has since 2022, that Russia should not be represented in international sport competitions while Russia's illegal and unjustifiable full-scale invasion against Ukraine continues," Canada's Secretary of State for sport, Adam van Koeverden, said, via The Athletic. "Canada will maintain restrictions on the participation of Russian athletes at events hosted in Canada that receive funding from the Government of Canada and explore further options to ensure that the Russian government is held accountable."

"The IIHF disagrees with this aspect of the ruling ​and maintains that its decisions were necessary to protect the safety and security of all participants and safeguard the integrity of its competitions," ‌the ⁠federation said.

REPUBLICAN CONGRESSMAN PRESSES NHL OVER ALEX OVECHKIN’S APPEARANCE IN PUTIN PARTY CAMPAIGN AD

In a brief statement, CAS cited a lack of sufficient evidence to support the IIHF’s security concerns. Russia's sports minister, Mikhail Degtyarev, told state television channel Vesti that "discrimination in hockey has been brought to an end," and "this place rightfully belongs to us."

Ukraine's ice hockey federation denounced the ruling while respecting the authority of the CAS.

"We wish to express deep outrage at this decision, taken amid a full-scale war. The threats that were the reason for suspending Russian teams in 2022 have not disappeared. On the contrary, they have only intensified," the federation said on its website.

"We believe that the safety of participants and ​the integrity of international sport ​cannot be considered separately ⁠from the realities of the war that Russia continues to wage against Ukraine."

Other countries to oppose the decision include Germany, Finland, Czechia, Sweden and Austria.

The first tournament to be affected by the change will be the World Juniors, and Germany will host the World Championships next year.

CLICK HERE TO DOWNLOAD THE FOX NEWS APP

Notable NHL players include Alex Ovechkin, Nikita Kucherov, Kirill Kaprizov, Andrei Svechnikov and Artemi Panarin, among others.

Reuters and The Associated Press contributed to this report.