Russian prosecutors have charged three suspects over involvement in last month’s bombing attack in the Saint Petersburg metro.
Russia's Investigative Committee said on Thursday that the three, Bakhram Ergashev, Ibragimzhon Ermatov and Makhamadyusuf Mirzaalimov, were charged with involvement in a "terrorist act."
Investigators said the trio was also charged with having illegally used explosives in the April 3 attack, which killed 15 people. The committee added that seven other suspects will be charged in the near future.
Meanwhile, Russia’s Federal Security Service (FSB) said that another suspect had been arrested on Thursday over links to the metro bombing.
The FSB said the individual who bore the last name Ermatov had reportedly been involved in the "illicit trafficking of explosives linked to” the bombing.
A group suspected of links to al-Qaeda has claimed responsibility for the attack, saying the bombing was a response to Russia’s involvement in the war against militants, apparently making a reference to Moscow’s campaign against terrorists in Syria.
Russian investigators had initially suspected that elements linked to the Daesh Takfiri terrorist group were behind the attack. Akbarjon Djalilov, a 22-year-old of Kyrgyz origin who died in the blast, is thought to have carried out the attack.
Russia started a military campaign in Syria in September 2015 at the official request of the government in Damascus.
The airstrikes, which initially targeted Daesh east of Syria, later expanded to attack positions of groups linked to al-Qaeda in the north. That greatly boosted Syria’s position in the war as the Syrian military and its allies managed to purge militants from the key city of Aleppo late last year.
Estimates suggest that thousands of Russian nationals have joined the militant groups in Syria since the war began six years ago.
Besides helping Damascus with the anti-terror campaign, Russia has defended its military presence in Syria as a preemptive measure aimed at preventing possible terror attacks on its soil when militants return home.