Russian authorities say they have charged three suspects in the April 3 bombing that killed 16 people on a subway train in St. Petersburg.
The federal Investigative Committee said on May 11 that Bakhram Ergashev, Ibragimjon Ermatov, and Makhamadyusuf Mirzaalimov had been charged with involvement in a "terrorist act" and the illegal possession or use of explosives.
Seven other suspects will be charged in the near future, investigators said.
Russian authorities say the attack was carried out by 22-year-old Kyrgyz-born Russian citizen Akbarjon Jalilov, who was among the dead.
All 10 arrested suspects are of Central Asian origin, but the Investigative Committee did not identify the citizenship of the three men charged.
A little-known group called the Imam Shamil Battalion has claimed responsibility for the bombing, according to a U.S.-based organization that monitors extremist messages.