US Vice-President Joe Biden is in Turkey to meet President Recep Tayyip Erdogan, aiming to push for a bigger Turkish role in the fight against he IS militant group.
Turkey has said such a role would have to be linked with plans to remove Syrian President Bashar al-Assad, the BBC reported.
Turkey has pressed for a no-fly zone in Syria but has not won US backing.
Biden and Erdogan have also had a public row over foreign militants crossing Turkey’s border with Syria.
On Friday, Biden held talks with Prime Minister Ahmet Davutoglu, who praised the “deep-rooted” relationship between the countries.
Biden said: “We’ve been friends for a long time and one of the great advantages of being back in Turkey with a friend and NATO ally is we’re always direct with one another.
The talks between Biden and Erdogan will focus on Turkey’s role in the US-led coalition against IS.
They will also look at Turkey’s efforts to stop the flow of foreign militants joining IS via Turkey, and Turkish assistance to more than 1.6 million refugees on its soil.
The BBC said Biden may receive the red-carpet treatment but relations are not good.
Last month, the US vice-president said that Erdogan had privately admitted Turkey had allowed foreign militants to enter Syria.
This was angrily denied by the Turkish president, who called his relationship with Biden “history”.
The vice-president’s office said he had apologized, but Biden then said it was not an apology, merely a clarification.
So far, Turkey’s main contribution to the campaign against IS has been to allow some Kurdish fighters from Iraq to travel through Turkey to assist in defending the Syrian town of Kobane near Turkey’s border.
