Then-US Vice President Joe Biden (L) meets with Turkish President Recep Tayyip Erdogan, at Beylerbeyi Palace, in Istanbul, Turkey, Nov. 22, 2014. Photo: Reuters / Murad Sezer / File.

Turkish President Recep Tayyip Erdogan on Tuesday congratulated US President-elect Joe Biden and Vice President-elect Kamala Harris on their victory in the 2020 presidential election, after years of rising tension between the NATO allies.

Bilateral ties have become strained over a host of issues, including Turkey’s purchase of Russian S-400 missile defense systems, differences in policy on Syria and the detention of US consulate employees and citizens in Turkey.

But the personal rapport between Erdogan and President Donald Trump have kept relations from deteriorating further.

In his message on Tuesday, Erdogan reiterated Ankara’s “determination to work closely with the US administration” in the coming period. He said “the strong cooperation and alliance” between the two countries would continue to contribute to world peace.

The presidency said on Tuesday that Erdogan had sent a message to Trump as well.

“No matter how the official election results manifest, I thank you for the sincere and determined vision you have put forth for Turkey-US relations to develop on the basis of our mutual interests and values during your presidency in the last four years,” Erdogan said in the message.

Analysts have said the US-Turkish relations could be further strained under a Biden administration, concerns that have also led to a decline in Turkey’s lira.

Soli Ozel, lecturer on international relations at Istanbul’s Kadir Has University, said Turkey was “not an easily dispensable partner” and he did not “share this infantile view that he (Biden) is a Turkey hater. He is probably the one person in the American establishment who knows Turkey best.”

Yet the S-400 dispute, as well as the Iran sanctions-busting case against Turkish state lender Halkbank in the United States, could prove bigger issues under Biden, Ozel said.

He said Biden was also likely to pressure Turkey on topics such as human rights and rule of law issues.