US Vice President Joe Biden will travel to Ankara on Wednesday in a bid to improve strained ties between the two countries. However, recent developments have made the relationship between Turkey and the US even stormier.

It may not be an easy visit to Ankara for US Vice President Joe Biden, as he tries to repair strained ties with Turkey.

Turkish President Recep Tayyip Erdogan has demanded that the US extradite cleric Fethullah Gulen. Ankara pinpointed him as an orchestrator behind country's coup attempt in July.

The US has asked for solid evidence to prove the accusations.

And Washington's hesitation made Ankara question if both countries were still allies.

"We say to America: aren't we strategic partners? Don't we have extradition treaties? If that's the case, when you ask for terrorists to be extradited we didn't ask for documents. Based only on the extradition treaty, we immediately returned the terrorists to you. And now we want a terrorist from you and the return of this terrorist is subject to the extradition treaty," said Recep Tayyip Erdogan.

The stalling of Gulen's extradition will have serious consequences on bilateral relations, says Professor Gulnur Aybet, the Head of Department of Political Science and International Relations at Bahcesehir University.

"And people have an expectation that Gulen should be returned to Turkey immediately. And if this doesn't happen because of the ongoing hurdles in the legal case, I think this should be explained better to Turkey.""If the extradition request is refused or delayed I'm afraid that's going to have serious repercussions for the Turkish-US relationship," said Prof. Gulnur Aybet from Bahcesehir University.

Professor Aybet adds that the bitter feeling over Washington's ambivalence is not only felt in the Turkish government, but also shared among the Turkish public.

However, Gulen is not the only problem standing between the two countries.

Turkey turning to Russia is the last thing Washington wants to see. Biden is expected to use time in Ankara to convey that the US still needs and values Turkey as a key NATO ally.

Early this month, President Erdogan shook hands with his Russian counterpart Vladimir Putin in Moscow. Both countries recently renewed strained ties.

Putin was the first foreign leader to express his support for Erdogan after the coup happened.

"Clearly, President Erdogan is sending a message by getting closer to Russia and getting closer to Iran that he is unhappy with the attitude of the West. Now Turkey is still going to remain a member of NATO, still an aspirant for EU membership, but nonetheless the atmosphere that governs the relationship between Turkey and the Western countries is worse," said Bulent Aliriza, director of Turkey Project Center for Strategic and International Studies.

Tensions between US and Turkey were already bubbling even before the coup.

The US has been backing Kurdish forces in the fight against ISIL. But the Kurds, who have taken most of the area just south of the Turkish-Syrian border, are considered as separatists by Turkey.

With so many issues on the table, it remains vague if Washington will be able to fully repair ties with Biden's visit.