The supplies "are in accordance with international law and in line with all formalities and existing contracts (between the Russian and Syrian government)," the source told the Russian Kommersant daily on Thursday.
The weaponry and military hardware are needed to help the Syrian army counter the advances of ISIL terrorists, who have ceased areas in the country, the source explained, expressing confidence that the aid will significantly contribute to anti-ISIL efforts.
According to Russian President Vladimir Putin, Russia provides "considerable" support to Syria in terms of equipment, training and weaponry.
Russian specialists were sent to Syria to teach local armed forces to operate Russian weapons.
On Wednesday, Russian Foreign Ministry Spokeswoman Maria Zakharova stressed that Russian military specialists deployed in Syria are not participating in military operations in the conflict-torn country and are limited to an "advisory role".
Syria has been grappling with a deadly crisis since March 2011. The violence fuelled by Takfiri groups has so far claimed the lives of over 240,000 people, according to reports.
Russia has been engaged in international efforts to find a political solution to the ongoing conflict in Syria and has been providing humanitarian aid to the conflict-torn country.
Last week Putin said that Moscow and Washington were discussing the creation of an international anti-terrorism coalition, but cautioned that it was too early to discuss Russia getting involved in direct military action against ISIL militants.
The United States is leading an international coalition that has been conducting airstrikes allegedly against ISIL positions in Iraq and Syria since 2014.
Russia has repeatedly criticized the US-led coalition for not seeking approval from the UN Security Council and the Syrian government before launching the airstrikes; FNA reported.