Moscow attack death toll rises to 137, Putin to convene security council

Russia's investigative committee says the death toll in Friday's mass shooting at a concert hall on the outskirts of Moscow has risen to 137.

Russia's health ministry says 180 people have been hospitalized and that 142 of them are receiving in-patient treatment.

The attack occurred on Friday evening in the city of Krasnogorsk, northwest of the capital. Gunmen opened fire on concertgoers in the music hall and the building went up in flames.

Russia designated March 24 as a day of nationwide mourning. President Vladimir Putin lit a candle at a church at his residence outside Moscow on Sunday to mourn the victims.

Russia's state media report that Putin is planning to hold a meeting of the security council to discuss responses to the deadly attack.

Russian authorities say they have detained 11 people, including four directly involved in the shooting. The authorities released a video showing the suspects being led to investigative committee headquarters.

The Amaq news agency, which is linked to the Islamic State militants, quoted sources as saying that the attack was carried out by the group's fighters. It released photos of four people it says were responsible for the attack.

A senior member of the lower house of Russia's National Assembly said on social media that two suspects had been detained in Russia's western region of Bryansk. He said that weapons, including a pistol, and passports from Tajikistan were found in the suspects' car.

Russia's presidential office says Putin talked over the phone with Tajik President Emomali Rahmon and agreed to intensify their joint counter-terrorism efforts.

Meanwhile, referring to 11 people who were detained, Putin said they attempted to escape and were heading towards Ukraine. He added that, according to information, "a window was prepared for them on the Ukrainian side to cross the state border."

An independent Russian media outlet reports that pro-Kremlin media have been directed by the Russian president's administration to spotlight the "Ukrainian trace" in discussions about the concert hall attack.

Ukraine has flatly denied any involvement in the attack. It is concerned that Russia may use the incident as a pretext to step up its offensive in Ukraine.