Ankara, Dec 31 (IANS): Turkey is being used as the main route for smuggling weapons to terrorist groups operating in Iraq and Syria, the UN has said.

Militant groups such as the Islamic State (IS) and Al-Qaeda affiliated Nusra Front in Iraq and Syria have been receiving weapons and equipment smuggled "primarily by routes that run through Turkey," Press TV reported, citing Tuesday's report by the UN Analytical Support and Sanctions Implementation Monitoring Team.

They have also seized some of their weapons "from the armed forces of Iraq or (to a lesser extent) the Syrian Arab Republic," the report added.

Senior Iraqi and Syrian officials have repeatedly criticized Turkey over links to the militants, including Turkish involvement in buying oil from both the IS and Nusra Front.

The IS militants "control a number of oil fields in Syria and Iraq and they smuggle the oil overland through truck and middlemen to Turkey or towards other countries," Iraqi Finance Minister Hoshyar Zebari told a news channel Dec 12.

In September, EU Ambassador to Iraq Jana Hybaskova revealed that some EU member states have purchased oil from the IS despite their rhetoric against the group.

US intelligence officials estimate that the IS militants earn more than USD 3 million a day from illegal oil sales, theft, human trafficking and ransom. They said the militants sell oil and other products via established networks in Turkey, Jordan and Iraq's Kurdistan region.

Turkey has denied reports of involvement in IS' smuggling operations.

The IS militants control some parts of Syria and Iraq. They have engaged in crimes against humanity in the areas under their control.