Several sources report that since December, dozens of Antonov transports have been delivering to Syria armored vehicles, surveillance equipment, radars, electronic warfare systems, spare parts for helicopters and various weapons including guided bombs for planes. The Reuters report comes less than a week before a critical conference on Syria’s future opens in Switzerland. Russian spokesmen have not confirmed it apart from stressing that Moscow violates no international laws and does not sell Damascus offensive weapons. The US State Department said it had no independent confirmation of the report, but it would raise concerns if true. Russian drones are also reported helping Syrian forces track rebel positions for precision artillery strikes.