Turkish President and Iranian counterpart say the two states to co-operate more over regional crises, such as Iraq and Syria.
Turkey's President Recep Tayyip Erdogan held a top-level meeting with his Iranian counterpart Hassan Rouhani in Tehran on Wednesday.
Erdogan’s visit comes at a time where several regional developments have prompted neighbours Turkey and Iran to work on closer ties.
One of these developments is the referendum in favour of independence in northern Iraq held by the Kurdish Regional Government (KRG).
TRT World's Hasan Abdullah has this report.
Speaking at a joint press conference with Rouhani on Wednesday afternoon, Erdogan said stronger steps would be taken in relation to the non-binding independence referendum in northern Iraq.
Both countries opposed the referendum and are opposed to any moves towards independence for the KRG-controlled territory.
“What is the purpose of the referendum in Northern Iraq Regional Administration? No one recognises you other than Israel. A decision made with Mossad can not be legitimate, it is illegitimate,” said Erdogan.
He said Ankara and Tehran would not recognise the referendum.
Speaking about developments in war-torn Syria, Erdogan stressed the importance of the Astana talks, which are being conducted by Iran, Turkey and Russia, in order to keep their fight against Jabhat Fateh al Sham and Daesh. He also said that de-escalation zones were very important for Turkey.
For his part, Rouhani underlined the importance of co-operation between Turkey and Iran to "combat terrorism" in the region.
He also said Tehran would back steps taken by the central Iraqi government and denounced the KRG's referendum move.
"We want security and stability in the Middle East ... the independence referendum in Iraq's Kurdistan is a sectarian plot by foreign countries and is rejected by Tehran and Ankara. Turkey, Iran and Iraq should take serious measures," said Rouhani.
He added that the two countries will continue their fight against terror groups, such as Daesh, Jabhat Fateh al Sham and the PKK.
Improving trade relations
Erdogan says the trade volume target of $30 billion between two countries was at the top of the agenda. Both leaders also agreed to trade in their respective currencies; and Turkey said it planned to import more natural gas from Iran.
Rouhani said that in order to improve bilateral trade, three of the border gates on their common borders will be kept open for 24 hours a day.
From Thursday onwards, two of them will be open for 24 hours. The third one is expected to operate on a 24-hour basis in the near future once certain technical problems are resolved.
Erdogan underlined that bilateral trade volume is around $10 billion, and these high-level visits should help to increase bilateral trade.
Measures against the KRG
Turkey and Iran have already joined Baghdad in warning the KRG that it faces having economic sanctions imposed on the region under its control.
The two countries launched joint-military exercises with Iraqi troops near their respective borders with the KRG-controlled territory.
Erdogan’s trip to Iran comes a week after Russia's President Vladimir Putin visited Ankara, as ties between Turkey and both Iran and Russia grow amid common regional security concerns, especially in Syria.
Much like the meeting with Putin, the KRG independence referendum in Iraq, the Astana process in Syria and bilateral trade are likely to top the agenda.
While Iran and Turkey have different policies on Syria, they have both opposed the KRG independence referendum.
Erdogan is also due to meet Iranian Supreme Leader Ayatollah Ali Khamenei on his one-day official trip to Iran.