Russia's UN Ambassador Vitaly Churkin said in a letter to the UN Security Council circulated today that Turkey is the main supplier of weapons and ammunition to IS fighters. He said the transfers are overseen by the country's National Intelligence Organization.
Turkey's UN Mission did not immediately answer calls seeking comment on the Russian letter.
Russia's recent air campaign has helped close ally Syrian army make broad advances on the ground. Turkey, Saudi Arabia and other regional players have backed opponents of Syrian President Bashar Assad and oppose any strengthening of the Damascus government.