US Vice President Joe Biden (L) attends a bilateral meeting with Turkish President Tayyip Erdogan in Washington March 31, 2016. REUTERS/Joshua Roberts

US President Joe Biden and Turkish President Tayyip Erdogan will discuss problematic bilateral ties on Monday including Ankara’s purchase of Russian S-400 missiles, but there is little hope they will resolve any of several disputes that divide NATO.

The two leaders will hold their first face-to-face talks since Biden took office in January on the sidelines of a NATO summit in Brussels.

Turkey has the Western alliance’s second-biggest military after the United States but disagreements over Syria, human rights, the treatment of Armenians in the Ottoman Empire and tensions in the eastern Mediterranean have strained their ties.

As president, Biden has recognized the 1915 massacre of Armenians as genocide and stepped up criticism of Turkey’s human rights record, adopting a cooler tone towards Erdogan than his predecessor Donald Trump.

White House national security adviser Jake Sullivan said the two leaders would also touch on Afghanistan, Libya and China.

“They will talk about political and economic issues that are more challenging … that have been challenges in our relationship, including human rights-related issues,” Sullivan told reporters on arriving in Brussels late on Sunday.

Before the summit started, Erdogan met with French President Emmanuel Macron. Ankara and Paris have recently been at odds over Syria, Libya, and Turkish criticism of the fight against what Macron calls Islamist separatism, among other issues.

Macron and Erdogan discussed working together on Libya and Syria while the French president said his country and its secular laws respected all religions, including Islam.

Leaving Turkey, Erdogan said that he expected from Biden an “unconditional approach” to moving on from past troubles.

“Turkey is not just any country, it is an allied country. We are two NATO allies,” he told reporters.

“There are many issues regarding defense industry that were left on the table. The most important one of these is the F-35 issue,” Erdogan said of Washington’s decision to remove Turkey from a fighter jet program.

One area where Erdogan hopes to showcase a central Turkish role in the NATO alliance is in Afghanistan, where Turkey has offered to guard and operate Kabul airport to secure access to the country after the US-prompted NATO withdrawal.

But with so many points of contention, hopes for any substantial breakthrough in the strained relationship are slim.

“While both sides are expected to pursue some pragmatic engagement and neither is interested in a showdown, the meeting will not provide Erdogan with any meaningful dividend,” consultancy Teneo said in a note ahead of the talks.