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.

A spokesman for the GKNB security service identified the suspect as Akbarzhon Jalilov, born in the city of Osh in 1995. He provided no other details.

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

Monday's blast on board a metro train in St Petersburg killed 11 people and wounded 45.