Citing Russia’s Investigative Committee, Russian media reports say the death toll in the terrorist attack at the Crocus City Hall in in Krasnogorsk has risen to 139, including three children.  

Recall, Russian news agencies have reported that Russian President Vladimir Putin was informed Saturday that four suspected gunmen responsible for the attack were arrested near Russia's western border with Ukraine.

Seven others have been detained and the search for other accomplices is ongoing, the state news outlets reported.

The Islamic State (IS) terrorist group claimed responsibility for the deadly attack Friday night, in which gunmen opened fire on concertgoers at one of Moscow's largest entertainment complexes. The attackers then set the complex on fire.

Earlier, Russian media posted unverified photos of a car they said belonged to some of the attackers near Russia's western border, and a Russian MP said at least two suspects were detained after a car chase and a shootout, though neither of these has been verified or confirmed by Russian authorities.

The death toll as a result of the terrorist attack has reportedly increased to 139, including three children.   The local governor said 121 people remain hospitalized.

Investigators said more than 500 rounds of ammunition and 28 magazines, as well as two Kalashnikov assault rifles, were found at the scene.