Iranian President Hassan Rouhani and his Turkish counterpart Recep Tayyip Erdogan, who is visiting Tehran at the invitation of his Iranian counterpart, as well as a number of other senior officials from the two countries attended the ceremony.

During the ceremony, which was held after the two presidents' joint press conference, Rouhani and Erdogan underscored the necessity for further expansion of diplomatic and economic ties between the two countries.

They considered the signing of the documents as an important step in the development of Tehran-Ankara relations.

Earlier in the Tuesday meeting between the two presidents, they conferred on several economic issues including the reinforcement of their respective national currencies.

Erdogan also negotiated with Rouhani on Turkey's gas imports from Iran, and asked the Iranian side to lower its gas prices.

Turkey is purchasing the most expensive and largest amount of natural gas from Iran, he claimed, adding that Ankara would boost its gas imports if Tehran lowers its prices.

Iran and Turkey have plans to hike up the volume of their trade exchange to $30 billion by the end of 2015.