FSB head Alexander Bortnikov is on the wires with this:
"We believe the action was prepared both by the radical Islamists themselves and, of course, facilitated by Western special services, and Ukraine's special services themselves have a direct connection to this,"
He repeated that attackers were trying to flee to Ukraine.
"I'll let you in on a little secret: they were going to be greeted as heroes on the other side," Bortnikov said.
He didn't offer any evidence.