"Russian planes are sending to Syria both military equipment in accordance with current contracts and humanitarian aid," Lavrov told reporters in Moscow.

"We have never made our military presence [in Syria] a secret," he said, denying claims that Russia was beefing up its presence in the war-torn country. "Russia is not taking any additional steps," he added.

On Wednesday, NATO Secretary General Jens Stoltenberg said he was "concerned about reports about the increased Russian military presence in Syria. That will not contribute to solving the conflict. I think it is important to now support all efforts to find a political solution to the conflict in Syria."

Stoltenberg was referring to media reports claiming that Moscow was sending reinforcements and even ground troops or special forces to Syria, which the Kremlin has denied.

Russia maintains that the arms supplies to Syrian President Bashar al-Assad's regime are part of international efforts to combat "Islamic State" ("IS"). Russian President Vladimir Putin said last week that Russia could deploy its troops to Syria to help fight IS, and that he was "looking at various options."

Russia believes that defeating IS in Syria is impossible without Assad, whereas the US and NATO maintain that Assad is the cause of the current crisis in Syria. Washington has repeatedly warned Moscow not to bolster its presence there.

Lavrov says not involving the Syrian military in a US-led coalition to fight IS, which has captured large areas of Syria and Iraq in the past year, was a "colossal mistake."

ng/kms (AFP, AP, dpa)