“Our work on Patriot missiles and other systems compatible with NATO will continue,” Turkish Prime Minister Binali Yildirim told reporters on March 23.

Ankara “looks positively towards all kinds of joint work” that will guarantee the security of the southern borders of the country, said Yildirim.

“The U.S. is still our ally despite its mistakes in the region of Syria,” he said.

“We have not given up compatible systems for NATO,” Yildirim said. He added that this work would not be an “alternative” to the Russian S-400 anti-missile defense systems that Ankara had decided to purchase.

“The U.S. is still our ally despite its mistakes in the region of Syria,” he said.

The S-400 systems that Turkey buys from Russia are “independent” systems and they do not change the Turkish government’s assessment for Patriot systems, the prime minister noted.

In December last year, Turkey and Russia signed an accord for Moscow to supply Ankara with S-400 surface-to-air missile batteries, finalizing a deal set to deepen military ties between NATO member Turkey and the Kremlin.

Turkey and the U.S. have been trying to iron out a number of issues, including a decision by Ankara to purchase the Russian S-400 systems, which could be subject to U.S. sanctions.

“The U.S. understands Turkey’s desire to improve its air defenses. But we are concerned and have said so publicly about the potential acquisition of Russian S-400 missiles, which would have implications for NATO interoperability and which would potentially expose Turkey to sanctions due to the new sanctions law recently passed by Congress,” a U.S. administration official told the Hurriyet Daily News in February.

“We are also working with Turkey cooperatively. This issue was discussed in Ankara last week, about how we can find better solutions to help Turkey’s air defense needs, which we understand are legitimate,” said the official, speaking on condition of anonymity, referring to discussions between U.S. Secretary of State Rex Tillerson and Turkish officials on Feb. 15-16.

Tillerson visited Ankara last month and the two sides agreed to establish working groups, which will also address the issue of Turkey’s purchase of Russian systems and possible sanctions.

Tina Kaidanow from the U.S. Department of State is expected to visit Turkey late March for talks on the Patriot missile systems.

Reporter’s code: 50101