Biden and Erdogan
Biden and Erdogan Reuters

US President Joe Biden on Sunday told Turkish President Recep Tayyip Erdogan his request for F-16 fighter jets had to go through a process in the United States, while Erdogan said his counterpart was "positive" toward the jet sale, Reuters reported.

Biden and Erdogan met on the sidelines of the G20 summit in Rome on Sunday. Biden also raised the issue of human rights, a US senior administration official told reporters.

"President Biden reaffirmed our defense partnership and Turkey's importance as a NATO Ally, but noted US concerns over Turkey's possession of the Russian S-400 missile system," the White House said in a statement after the meeting.

The Turkish presidency said the two leaders had agreed to form a joint mechanism to strengthen ties, while a senior Turkish official said the talks were held in "a very positive atmosphere".

Erdogan, who spoke to reporters after the meeting, said he reiterated to Biden Turkey's opposition to US support for the Syrian Kurdish YPG.

Relations between the US and Turkey have soured in recent years, after Turkey's purchase of the Russian S-400 missile defense system that the US believes can be used to spy on Western defenses.

In response to the purchase, the US sanctioned Turkey’s military procurement agency and expelled Turkey from the F-35 program, under which Western allies produce the next-generation fighter jet's parts and secure its early purchasing rights.

Turkey has repeatedly made clear it will use the Russian system despite US threats of sanctions.

Despite the tensions, Erdogan said earlier this month that the US had proposed the sale of F-16 fighter jets to Turkey in return for its investment in the F-35 program.

US lawmakers have urged the Biden administration not to sell F-16s to Turkey and threatened to block any such exports on the grounds that Turkey had purchased Russian missile defense systems and "behaved like an adversary".

Erdogan said on Sunday he asked Biden for support in getting US lawmakers to back the sale.

"While I saw Mr. Biden's positive approach on this matter, another aspect of the issue is the House of Representatives and Senate," he said, according to Reuters.