Sergei Lavrov said the cooperation between the countries was "in line with the international law" and "in the interests of strengthening stability and maintaining security" in regions close to Russia's borders.
"We are not doing anything that could upset the balance of power in this or that region," Lavrov told reporters.
During last month's talks with Syrian President Bashar al-Assad in Moscow, Lavrov confirmed that Russia was ready to supply Syria with defensive weapons. Media reports said earlier Moscow and Damascus had agreed on deliveries of the latest Russian MiG-29SMT fighter.
Syria, a major importer of Russian weapons, also bought 36 Pantsir S1E air-defense systems from Russia, and hopes to receive Strelets short-range air defense systems, Iskander tactical missile systems, Yak-130 aircraft and two Amur-1650 submarines.
Media has also reported Russian plans to rebuild the Soviet-era Navy maintenance site in the northern Syrian port of Tartus, the only Russian foothold in the Mediterranean, and turn it into a permanent naval base.
The reports say about 10 Russian warships and three floating piers are deployed there while Russia expands the port and builds a dock in nearby El-Latakia. There has been no official confirmation of the reports.
Israel and the United States are sensitive about Russian-Syrian military and technical cooperation, fearing not only a reinforcement of Syria's armed forces, but also the possibility that modern weapons could fall into the hands of Hezbollah fighters in Lebanon or be passed on to Iran, in violation of the existing international embargo.