The U.S. Embassy in Moscow has warned of a credible threat of a "mass casualty" event at the Tsaritsyno Museum Reserve, a popular tourist attraction in Moscow, according to a report by Fox News.

According to Fox News, the embassy urged people to avoid the area. The outlet's summary describes the threat as credible and as one involving a mass casualty event, but it does not say what specific threat the embassy identified.

Fox News reported that the warning named the Tsaritsyno Museum Reserve as the location of the threat. The summary does not provide the embassy's exact wording, the basis for its assessment, or the time at which the warning was issued.

Fox News's headline and summary use similar language, describing a credible threat tied to a single location. The headline identifies that location as a popular tourist attraction in Moscow, and the summary identifies it as the Tsaritsyno Museum Reserve.

Neither the headline nor the summary of the Fox News report includes a comment from Russian authorities or from officials at the museum reserve. Both identify the U.S. Embassy as the source of the warning, and no other account of the warning was available for this story to compare with it.

Because this story draws on a single Fox News report, its facts are limited to what that outlet published about the embassy warning. Key questions remain unanswered in the available reporting, including what the threat involves, whether any authority has confirmed it, and whether the embassy has issued further notices. The Fox News summary does not address any of these points.

Sources: Fox News: US Embassy warns of credible 'mass casualty' threat at popular Moscow tourist attraction.