Suspects in Russia concert hall attack charged with terrorism

Russian authorities have charged four suspects with terrorism over Friday's deadly attack at a concert hall on the outskirts of Moscow.

The Russian Investigative Committee says 137 people died in the incident in the city of Krasnogorsk. Health officials say 182 are undergoing treatment at hospitals.

Russia's state-run Tass news agency quoted a venue official as saying on Monday that as many as 5,000 people were evacuated from the building after the attack.

Russian authorities have detained 11 people in connection with the deadly attack. By Monday, officials indicted four suspects, whom state-run media have identified as Tajik nationals.

Russia's presidential office disclosed on Sunday that Russian President Vladimir Putin and Tajik President Emomali Rahmon spoke on the phone and agreed to intensify their joint counterterrorism efforts.

The Amaq news agency, which is linked to Islamic State militants, says the attack was carried out by the group's members.

However, Putin claims that Ukraine was involved.

In his address to the nation on Friday, Putin compared the attackers and their "demonstrative execution" to the Nazis, "who once carried out massacres in the occupied territories."

Ukraine has flatly denied involvement in the incident. But speculation is growing that the Putin administration may use the terror attack as a pretext to intensify its offensive against Ukraine.