Fourteen people were killed in the April 3 attack.
Russian authorities detained one of the people suspected of organizing the St. Petersburg metro terrorist attack two weeks ago, TASS, the Russian government-owned news agency, reported Monday.
A suspect accused of plotting the St Petersburg bombing attack has been arrested near Moscow, according to Russian officials.
Jalilov was killed in the explosion.
Russia's FSB security service said on Monday that it had detained a 27-year-old man in the Moscow suburb of Odintsovo.
RIA reported that the FSB described him in a statement as one of the organisers of the attack and said he had trained Jalilov.
Russia's Federal Security Service has detained a person who could have been involved in the explosion in the St. Petersburg Metro, as part of the criminal investigation launched by the Investigative Committee, the center said in a statement, RT reports.
At the time of his arrest, Azimov was reportedly carrying a pistol and a parcel containing two smartphones.
Jalilov is said to have detonated his device after a metro train left St Petersburg's Sennaya Ploshchad station, heading south for Tekhnologichesky Institut on the blue, north-south metro line.
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