Russian President Vladimir Putin has vowed to punish those responsible for the deadly attack on a Moscow concert hall that killed 133 people, after authorities said the four main suspects were apprehended near the Ukrainian border.
Friday's assault on Crocus City Hall was the deadliest terror attack on Russia's capital in decades, coming less than a week after Putin won a stage-managed election, tightening his grip on the country he has ruled since the turn of the century.
The terrorist group ISIS claimed responsibility for the fatal incident. A US official stated on Friday that Washington had no reason to doubt ISIS' claim.
On Saturday, UN Secretary-General Antonio Guterres called for global cooperation against ISIS in response to the latest developments.
In a video statement released Saturday, Putin linked what he called a "barbaric terrorist attack" to Ukraine while also expressing deep condolences and declaring Sunday as a national day of mourning.
According to him, the attackers "tried to hide and move towards Ukraine, where, according to preliminary data, a window was prepared for them on the Ukrainian side to cross the border."
Also on Saturday, the Committee reported that four men suspected of carrying out the attack were apprehended on Friday night near Russia's border with Ukraine.
"Special services and law enforcement agencies in the Bryansk region, near the border with Ukraine, detained four suspects from among those who committed a terrorist attack in the Crocus City Hall concert hall," the Senate Foreign Relations Committee stated.
This was also reported by Russian state media agency RIA Novosti, which stated that following the attack, the criminals "intended to cross the border of the Russian Federation and Ukraine and had relevant contacts on the Ukrainian side, the FSB said." The FSB, Russia's security agency, did not disclose the nature of the alleged contacts.