The US vice president Joe Biden is to meet the Turkish president and urge his country to take a bigger role in the fight against Isis.
Recep Tayyip Erdoğan has previously said he would only step up support against the Islamist militant group, which is also known as Islamic State, if the international community made plans to help remove Syrian president Bashar al-Assad.
Turkey is also involved in a long-standing struggle against separatist Kurdish groups in the east of its territory. Kurdish groups in neighbouring Iraq have been at the forefront of fighting against Isis, and observers say Turkey fears the influence the increasingly autonomous Iraqi Kurds could have in the region.
These factors so far appear to have made Turkey, a major regional power, reticent to attack Isis head-on.
On Friday, Mr Biden held talks with country’s Prime Minister Ahmet Davutoğlu. The US vice president 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. Friends don't let the other wonder about what they are thinking."
The talks with the country’s president will focus on Turkey’s role in the US-led coalition against Isis and the issue of foreign fighters travelling through Turkey to join the Islamist group.
Ahead of the talks, Mr Biden said the US government was in favour of the development of an oil pipeline from oilfields in southern Iraq to Turkey's Mediterranean port of Ceyhan, a project which Turkey has long advocated despite Iraqi concerns.
Turkey has cooperated in the fight against Isis to come degree, having allowed some Kurdish fighters from Iraq to travel through its territory to help defending the Syrian town of Kobane.
However last month Turkey also bombed fighters from the Kurdistan Workers' Party (PKK) inside its own territory while the same group was helping in the fight against Isis.