The FSB announces that it has arrested four more people accused of participating in the attack in Moscow

On March 22, gunmen stormed Crocus City Hall and set it on fire, killing more than 140 people in the deadliest attack in Russia in two decades.

In a statement issued on Monday, the FSB said it had arrested a group of four people in the southern region of Dagestan on Sunday who were “directly involved in financing and supplying the perpetrators of the terrorist attack committed on March 22 in Moscow’s Crocus City Hall with terrorist equipment.”

Earlier, Russian officials said they had arrested three people accused of planning terrorist attacks in the North Caucasus republic of Dagestan on Sunday.

The FSB added on Monday that four other foreign nationals were arrested during the operation in the regional capital Makhachkala and the nearby city of Caspian.

The Interfax news agency cited the FSB as releasing a video in which one of the detainees admits to supplying weapons to the perpetrators of the terrorist attack in Moscow.

Earlier, Russian authorities announced the arrest of 12 people believed to be involved in the attack, including four suspected terrorists who were identified as Tajik nationals.

The Islamic State (IS) group claimed responsibility for the attack, while Russian authorities claim that Ukraine and the West are responsible.

Ukraine and its Western allies dismiss Moscow’s accusations as absurd and deny any links.

Dagestan is a Muslim-majority region in Russia’s southern Caucasus region.