ST PETERSBURG, RUSSIA -- APRIL 3, 2017: Emergency workers at the entrance to Tekhnologichesky Institut station of the St Petersburg metro in the aftermath of an explosion which occurred in a train at 14:40 Moscow time; according to Russian National Antiterrorism Committee several people were killed in the explosion. Anton Vaganov/TASS (Photo by Peter Kovalev\TASS via Getty Images)
