Iran has agreed to supply oil to Syria, Tehran Times daily reported Wednesday.

Iranian and Syrian central banks signed an agreement in Tehran on Monday, with Iran agreeing to grant a credit line of 3.6 billion U.S. dollars to Syria, the report said.

Syria will pay back the oil loan by allowing the Iranians to invest in the country, said the report, which did not provide details about the deal.

Over the course of its two-year unrest, Syria has been facing serious problems in producing oil and its byproducts.

Iran has been the main regional ally of Damascus as its officials have repeatedly stressed Iran's support for a political solution to the ongoing Syrian crisis.