A suspect accused of helping to prepare the St Petersburg metro bombing has been detained near Moscow, Russian security officials say.
Russia's Federal Security Service (FSB) said the suspect was arrested in Odintsovo, a city just outside Moscow.
"At the moment, Abror Azimov has been brought to the Russian Investigative Committee for investigative activities", the Federal Security Service (FSB) in Russia said, according to TASS.
Fourteen people were killed and more than 50 wounded when Kyrgyz-born Russian Akbarzhon Jalilov detonated the device.
Authorities identified the bomber as Akbarjon Djalilov, 22. Now, there are 38 people hospitalized, and majority with wounds from splinters of the bomb.
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The FSB statement said Akhralovich was a "native of the Central Asia region" and allegedly had "trained the suicide attacker".
Numerous previous attacks were aimed at progressing separatist causes in Russia's North Caucasus, including movements in Chechnya and Dagestan.
A woman places flowers in honour of the victims of the April 3 blast on the platform of Technological Institute metro station in Saint Petersburg on April 4, 2017.
Two suspects in the St Petersburg bombing have already been detained in the same Moscow suburb.