Update(1950ET): The initial reports that ISIS has claimed responsibility for the terror attack in Moscow appeared rumor at first, and has still been subject of widespread scrutiny and debate, however, US media and government officials are saying that the Islamic State (or ISIS-K) statement is authentic. “A branch of the Islamic State claimed responsibility on Friday for the attack in Moscow that killed at least 40 people and injured about 100 others, and U.S. officials confirmed the claim shortly afterward,” The New York Times writes late in the day.

What’s more is that US intelligence knew there was to be an imminent attack on Moscow: “The United States collected intelligence in March that Islamic State-Khorasan, known as ISIS-K, the branch of the group based in Afghanistan, had been planning an attack on Moscow, according to officials. ISIS members have been active in Russia, one U.S. official said,” according to more from NYT.

The Kremlin had earlier in the day demanded answers of Washington explaining why the US Embassy in Moscow issued an alert earlier this month for all US nationals to avoid public venues and be extra vigilant. We previously reported on that early March embassy notification here. NY Times continues, citing US officials: “After a period of relative quiet, the Islamic State has been trying to increase its external attacks, according to U.S. counterterrorism officials. Most of those plots in Europe have been thwarted, prompting assessments that the group had diminished capabilities.”

Importantly, Russian state media and sources have been slow to report the ISIS-K claims, nor have state officials identified any culprits or group at this late hour. Russian media in general has not reflected Western press reports concerning the claims that ISIS-K was behind it, likely pending a deeper and ongoing investigation. It is possible that some of the gunmen may still be at large.

Speculation continues to run rampant, and there’s as yet been little that’s confirmed from Russian security services and authorities.

At least 40 were killed when a group of heavily armed, unidentified gunmen stormed Crocus City Hall music venue. Russia’s Health Ministry has released a list of names of 145 people who have been hospitalized in critical condition. Children are among them.

Below: video has emerged showing the moments the gunmen entered the concert hall, after randomly massacring people in the attached mall area of the complex…