A visit to Iran by Turkey's Foreign Minister Mevlut Cavusoglu on Wednesday highlighted their opposing views on the Syrian conflict, with both countries saying dialogue was needed to close gaps.

The gulf between Iran, Syrian President Bashar al-Assad's principal regional ally, and Turkey, which has supported Sunni rebels seeking to overthrow him, was underlined by Cavusoglu.

"We consider the Assad regime as not having legitimacy," he said at a joint press conference with his Iranian counterpart Mohammad Javad Zarif.

"Iran and Turkey have different positions but our countries are cooperating to find a common solution in Syria," Cavusoglu added.

Iran has strongly backed Assad, sending money and military advisers to Damascus as well as supporting him politically in the face of widespread international opposition.

Talks have been under way for months on a potential ceasefire between the Assad regime and rebel forces, but they have so far been fruitless.

More than 200,000 people have been killed in nearly four years and around half the population has fled their homes.

Cavusoglu's visit came with Syrian Prime Minister Wael al-Halaqi also in the Iranian capital for talks.

Zarif said that although Iran and Turkey had differences, they nevertheless faced "common enemies" and there was a "need to bring our positions together to stop terrorists entering Iraq and Syria."

"We all want peace established as soon as possible in Syria without foreign interference," Zarif added.