The likely suspect in a deadly blast in the Russian city of St. Petersburg is a Kyrgyz-born Russian citizen, Kyrgyzstan's security service said on Tuesday.Kyrgyz authorities identified the attacker as ​Akbarzhon Jalilov, who was born in Kyrgyzstan's Osh city in 1995.

A spokesman for the GKNB security service said it had received an official request from Russian security services to identify the suspect.

The Kyrgyz intelligence agency said it is cooperating with Russian authorities to help the investigation.

It is unclear whether the attack was a suicide bombing or whether the bomber got away.

The spokesman declined to name the suspect or provide any additional information.

There was no immediate claim of responsibility for the explosion, which comes after the Daesh terrorist group called for attacks on Russia in retribution for its military intervention in Syria.

Kyrgyzstan, a Central Asian nation of six million, is Russia's close political ally and hosts a Russian military airbase.

Meanwhile, St. Petersburg's Sennaya Ploshchad metro station has been closed after an anonymous phone call warned of another possible attack, Russian news agency RIA Novosti reported on Tuesday.

Another agency Interfax said its reporter had seen several fire engines outside the station.

A bomb blast tore through a subway train under Russia's second-largest city on Monday, killing 11 people and wounding more than 40.