Iran’s official line is that the visit by Raisi is about economic and commercial issues and the Palestinian issue is only a close second in the discussions.
Ankara said on Thursday a ground operation into Syria was one option it could consider. Turkey has mounted several previous incursions into northern Syria against the YPG.
Ankara increasingly focuses also on strikes near Sulimaniyeh, a city that is aligned with the Kurdish political party PUK
It is important to look back at how various forces involved in the Syrian turmoil go to this point in order to understand this complex conflict.
These groups were often part of the plethora of Syrian rebel groups that operated in northern Syria since the Syrian civil war began in 2011.
Unregistered Syrians have been ordered to leave Istanbul, a move seen as politically motivated in light of Turkey's recent elections and growing discontent with the refugee population.
Syria gave its approval on Thursday for the UN to use Bab al-Hawa for another six months, but with several conditions.
Many opposition politicians and critical journalists have been jailed in Turkey, meaning politics is far from free.
Erdogan has said he aims to ensure the return of one million refugees within a year to the opposition-held areas.
The discontent in Turkey over the nearly 4 million Syrian refugees has been a source of domestic pressure on Turkish President Recep Tayyip Erdoğan.