The Russian Federal Security Service, FSB, has disclosed the arrest of four persons over the terror attack on Moscow’s Crocus City Hall.

The attack, which took place on March 22, saw gunmen storming the concert venue and setting it ablaze, an incident that led to a death toll of over 140 people.

However, a statement by FSB disclosed that the arrests were made in the southern Dagestan region on Sunday.

The apprehended group is accused of being “directly involved in the financing and supply of terrorist means to the perpetrators of the terrorist act carried out on 22 March in the Crocus City Hall in Moscow.”

This development follows the Russian National Anti-terrorism Committee’s announcement on Sunday that three individuals planning a series of terrorist crimes had been detained.

The FSB’s subsequent statement expanded on this, specifying that four foreign nationals were arrested in the operations carried out in Makhachkala, the regional capital, and the nearby town of Kaspiysk.

Interfax news agency reported one of the detained individuals confessing in an FSB video, stating, “I took weapons to them, these guys who attacked Crocus City Hall. I took them weapons from Makhachkala.”

Prior to this revelation, Russian authorities had identified 12 people linked to the attack, including the suspected gunmen, all of whom are Tajik citizens.

The Islamic State (IS) has claimed responsibility for the massacre, which President Vladimir Putin has suggested might have connections to Ukraine and the West, a claim both Kyiv and Western countries have denied, accusing Moscow of exploiting the tragedy.

The arrests highlight ongoing concerns about security in Russia, especially in light of the FSB’s criticized response to the attack. Despite warnings from the US intelligence community about potential “extremist” threats in Moscow, the attack proceeded unimpeded.

The FSB, known for its regular announcements on foiling “terrorist cells,” has recently focused on detaining individuals it labels as pro-Ukrainian saboteurs.

President Putin has condemned the attack as a barbaric act of terrorism and vowed retribution against those responsible. Following the tragedy, he declared a national day of mourning and announced that security measures across Russia would be intensified.