The attack on the concert hall outside Moscow is reported to have resulted in deaths and injuries

U.S. officials confirm the Islamic State is responsible for the attack on Moscow on Friday, December 13 – the anniversary of the ISIS attack

An official from the U.S. confirmed to NPR that they believed that the attack was the work of an Islamic State affiliate group. The group, based in eastern Afghanistan, claimed responsibility for the attack on its Telegram channel.

The United States had warned Iran of a possible attack ahead of twin bombs that killed over 100 people at a memorial service for a top general who was killed by a United States air strike.

“The National Security Council has information about a planned terrorist attack in Moscow, which could be targeting large gatherings to include concerts,” said a statement by the spokesman for the council.

The attack on Friday in Moscow, like a January assault in Iran claimed by the group, could prompt a reassessment of its ability to strike outside its home territory.

In his remarks on Saturday, Putin made no mention of ISIS-K, instead accusing Ukrainian authorities of trying to help the four assailants escape via Ukraine.

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.

U.S. officials confirmed the claim of responsibility of the Islamic State for the attack in Moscow, which killed at least 40 people and injured around 100 others.

“It’s not my country,” Putin tells the Ukrainian president in an embassy in Moscow after the Dubrovka theater shooting

Some armed men in military fatigues entered the venue where concertgoers were waiting to see Picnic, a veteran Russian rock band.

The Ukrainians deny that there is any Ukrainian role. The adviser to the Ukrainian president claimed that the country had nothing to do with the shooting. It makes no sense whatsoever.”

U.S. National Security Council spokesman John Kirby said the images of the shooting were “horrible and hard to watch.” The US embassy in Moscow warns Americans to stay away from the area.

Moscow was the scene of a hostage crisis at the Dubrovka theater in 2002, in which Chechen gunmen demanding the withdrawal of Russian troops from Chechnya took some 800 theatergoers hostage. A raid by Russian security forces to end the crisis killed or caused the death of 172 people.

In his first televised address to the nation after the attacks, Russian President Putin said that the Kremlin had arrested all of the perpetrators, as well as seven others with suspected ties to the attack.

Putin said they tried to hide and moved towards Ukraine where a window was built to cross the state border.

The attack began late Friday after camouflaged gunmen carrying automatic assault rifles burst into the Crocus City Hall — a large shopping and entertainment center on the western outskirts of Moscow. Concertgoers had gathered at the venue to see the veteran Russian rock band Piknik.