The U.S. Department of State has criticized the preliminary gas treaty signed between Turkey and Iran, noting that the time is not right for investments in the Iranian energy sector.

"The decision about whether or not to do business in Iran belongs to the Turkish government and Turkish organizations. However, Iran has not proven a reliable partner for such treaties," said Sean McCormack, Spokesman for the Department of State, Hurriyet newspaper reports.

Iran and Turkey signed a memorandum on mutual agreement on energy cooperation. According to the agreement, Iran will convey several natural gas facilities in the Persian Gulf to Turkish companies while Iran will export its gas to Europe via Turkey.