ANKARA 

Turkey's defense minister and the U.S. special envoy for Syria discussed the situation in the northern Syrian town of Manbij and the east of Euphrates River on Thursday, according to a statement from Turkish Defense Ministry.

During their meeting at the NATO headquarters in Brussels, Hulusi Akar and James Jeffrey also discussed latest developments in Syria, the statement said.

Akar told Jeffrey that Turkey expected the U.S. to keep its promises on Manbij.

Last year, Ankara and Washington reached a deal stipulating the withdrawal of YPG/PKK terrorists from the town for the stability of the region, located in the northern part of Syria’s Aleppo province.

Akar reiterated Turkey's views for the formation of a safe zone in the east of the Euphrates River, the statement added.

Turkey previously underlined that a safe zone in this area would need to be free of YPG/PKK terrorists and that the region’s safety must be secured by Turkey.

The YPG is the Syrian offshoot of the PKK, a terrorist group recognized by Turkey, the U.S. and the EU which in its 30-year terror campaign has taken some 40,000 lives, including women and children.

The U.S. has claimed the YPG/PKK is an "ally" in the fight against Daesh over Turkey’s objections that one terrorist group could not be used to fight another. Ankara repeatedly cited the evidence that the YPG was not distinguishable from the PKK.

Speaking to Anadolu Agency after the meeting, Akar said the security of the F-35 fighter jet project and the jets themselves were of great importance to Turkey, as it is for the U.S.

"Efforts to deprive Turkey of F-35 fighter jet would significantly jeopardize the defense and deterrence of NATO," Akar stressed.

He said that Turkey had fulfilled all its responsibilities as a member of the F-35 program.

The F-35 project was a "commercial treaty" and that Turkey would defend all its rights in this respect, he added.

Turkey joined the F-35 Joint Strike Fighter Program in 2002 and has invested more than $1.25 billion. It also manufactures various aircraft parts for all F-35 variants and customers.

Stressing that Turkey expected a relationship with the U.S. based on mutual respect and friendship, he assumed that the two countries would be able to move forward on a "constructive road" on this issue.

He also reiterated Turkey's call for a formation of a working group with the participation of NATO on Turkey's purchase of Russian S-400 missiles in order to discuss the concerns of the U.S.

Tensions between the U.S. and Turkey have escalated in recent months over the Russian S-400 air defense systems purchase, which Washington said will jeopardize Turkey's role in the F-35 fighter jet program and could trigger sanctions.

Following protracted efforts to purchase an air defense system from the U.S. with no success, Ankara decided in 2017 to purchase the Russian S-400s.

U.S. officials urged Turkey to buy U.S. Patriot missiles, arguing the Russian system would be incompatible with NATO systems and expose the F-35s to possible Russian subterfuge.

Turkey, however, emphasized the S-400 would not be integrated into NATO systems and would not pose a threat to the alliance.

Turkey recently urged the formation of a commission to clarify any technical issues, but the U.S. has failed to respond to this proposal.