"Russia is not planning to sell -- Russia has sold and signed contracts a long time ago, and is completing supplies of the equipment -- which is anti-aircraft systems, according to the already signed contracts," Lavrov told reporters in Warsaw.
He added that "this is not forbidden by any international laws, this is defensive weaponry."
"It is designed for Syria as an importer to have in this situation an opportunity to defend itself from air strikes which, as we know, is not a completely fantastical scenario," he said.
Lavrov's comments came as Russian President Vladimir Putin and British Prime Minister David Cameron today discussed possible options and joint measures for ending the conflict in Syria during talks in southern Russian resort of Sochi.
A day earlier, US Secretary of State John Kerry warned against any Russian missiles sales to Syria saying it would be "destabilising" to the region as he seeks to build diplomatic efforts to end the bloody conflict.
"International arms deliveries to Syria must end and we must do everything to create a chance for a political solution," German Foreign Minister Guido Westerwelle insisted today in Warsaw at a joint press conference with Lavrov and Polish counterpart Radoslaw Sikorski.