Russia's President Vladimir Putin on Wednesday defended its arms trade against criticisms over its dealings with Syria, insisting only the United Nations could dictate restrictions on arms sales.

Putin defended Russia's right to trade weapons with whomever it wanted, without mentioning Syria but in an apparent reaction to recent attacks from the West over supplies to Syrian President Bashar al-Assad's regime.

"We operate on the premise that the only basis for limiting weapons supplies to any country is UN Security Council sanctions," Putin said as he opened a government meeting on military-technical cooperation.

"In all other cases, no one can on any pretext dictate to Russia or any other state with whom and how it should trade," he said, according to a transcript on the Kremlin website.

This week Turkey accused Russia of delivering "war equipment" to the Syrian government on board a Syrian plane, after the Turkish authorities forced the plane to land last week and seized the suspect cargo.

Russian Foreign Minister Sergei Lavrov said the cargo contained radar equipment and was being delivered legally, demanding that it be returned to its rightful owners.

However the incident led the US State Department to label Russia's Syria policy as "morally bankrupt".

Putin stood by Russia's current military-technical cooperation with Syria, which falls outside of UN sanctions.

"One-sided or collective bans and restrictions outside the framework of the UN Security Council, especially ones that are politically motivated, are not norms of international law," he said.

"We intend to continue to develop such cooperation and carry out absolutely all the obligations we take on."

Russia has infuriated Turkey and its Western allies by refusing to halt military cooperation with Syria, an ally dating back to Soviet times, despite the raging conflict in which activists say more than 32,000 people have died since March 2011.

Moscow has defiantly refused to take sides against Assad, and has slammed the West and Turkey for making clear their support for the rebels battling his regime.