Turkish President Recep Tayyip Erdogan met with Iranian President Hassan Rouhani on Tuesday, in a meeting fraught with tension after Erdogan accused Iran of trying to “dominate the Middle East” via its Houthi proxies in Yemen, leading 60 Iranian MPs to call for a cancellation of the trip.

In the meeting, which was followed by a chat with Iranian Supreme Leader Ayatollah Khamenei, Erdogan and Rouhani both called for an end to the fighting in Yemen, although neither made direct remarks about how that might be realized.

Iran has been backing the Shi’ite Houthi rebels, while Turkey has been siding with the Saudi-led coalition of Arab states conducting an airstrike campaign to push back the Houthis.

Turning to other regional battlegrounds, Erdogan said Iran and Turkey should be “mediators” in the conflicts in Iraq and Syria.

In terms of economics, “our both countries want to increase the (bilateral) trade volume from $14 billion in the previous year to nearly $30 billion,” Rouhani said in a joint press conference following his meeting with Erdogan.

He added that a final nuclear deal set for a June 30 deadline could see sanctions lifted on the Islamic regime and consequently improve economic ties between Iran and Turkey even further.

Turkish imports from Iran totaled around $10 billion last year, and Turkish exports to Iran were around $4 billion, with the ties keeping Iran afloat in the face of international sanctions. Turkey for its part is largely dependent on Iranian natural gas, with Iran being its second largest provider after Russia.

But Erdogan noted that “at the moment, we buy the most expensive gas from Iran. We do not want to be at this point. We should bring this down to a more suitable level.”

The Turkish Anadolu Agency reported that Turkey has called for Iran to reduce its gas prices by a quarter, which Iran has resolutely refused. It added that Iran is the most expensive exporter of gas to Turkey.

Erdogan also called for bilateral trade to be conducted in Turkish and Iranian currencies, so as to avoid fluctuations of the dollar and euro.