 Russian forensic experts were seen in Moscow collecting what appears to be fragments of a drone, one of a number of unmanned aerial vehicles that were used in an attack on the Russian capital in the early hours on May 30. Russia's emergency services were at the scene in at least three locations in Moscow and a spokeswoman for Russia's investigative committee Svetlana Petrenko said a forensic experts and investigators were following leads to identify those behind the drone attacks. Moscow Mayor Sergey Sabyanin said two people were injured, one of whom was hospitalized, in the early morning attack. Moscow's airports remained open. No deaths were reported. Drone attacks deep inside Russia have intensified in recent weeks, with strikes on oil pipeline installations and even the Kremlin earlier this month that Moscow has blamed on Ukraine.