UN chief Antonio Guterres “condemns in the strongest possible terms today’s terrorist attack at a concert hall outside Moscow, in which at least 40 people were reportedly killed and over 100 others injured,” spokesman Farhan Haq said in a statement.

Guterres “conveys his deep condolences to the bereaved families and the people and the Government of the Russian Federation,” he added, referring to Russia by its official name.

The Security Council also offered its condolences and urged all states “to cooperate actively with the Government of the Russian Federation, as well as all other relevant authorities” to hold perpetrators and backers of “these reprehensible acts of terrorism accountable and bring them to justice.”

“The members of the Security Council condemned in the strongest terms the heinous and cowardly terrorist attack,” their statement said.

The Islamic State group claimed the attack on Friday, saying in a statement on Telegram that its fighters had attacked “a large gathering” on Moscow’s outskirts and “retreated to their bases safely.”