A top US State Department official warned Ankara on Wednesday against buying a Russian missile defense system, stressing that there is still time for Washington to renege on a deal that would send F-35 fighter jets to Turkey.

Turkey officially received its first F-35 from Lockheed Martin last week, but it will remain on US soil as part of a training program.

“In this program, the US maintains custody of aircraft until they are transferred. That normally occurs after a lengthy training process,” Assistant Secretary of State Wess Mitchell said in comments to the Senate Foreign Relations committee.

“We believe that we have existing legal authorities that would allow us to withhold transfer under certain circumstances, including national security concerns,” he told lawmakers, adding “we believe that we continue to have time and ability to assure that Turkey does not move forward on S-400 before having to take a decision on F-35.

The sticking point is just one of many areas of friction between the NATO allies, which also includes US support for Kurdish forces in Syria and Iraq. Ankara has said their decision to buy the S-400 is due to Washington’s refusal to sell comparable US-made missile-defense systems, such as Patriot missiles.

“We needed [S-400] urgently because we did not have an air defense system. We even had troubles with buying simple rifles from the US due to concerns of the Congress. We had to buy it from someone,” as Turkish Foreign Minister Mevlut Cavusoglu told the Zeit newspaper last March.

If “the US government can guarantee that Congress will approve it,” the official said, Turkey would be happy to buy a US alternative.

THAAD to India?
In related news, as part of Washington’s efforts to step up military ties with India, the US is reportedly considering an effort to sell its Terminal High-Altitude Area Defense (THAAD) system to India. New Delhi has already concluded price negotiations with Moscow on the purchase of the S-400 system.

India’s Economic Times, which reported the possible lobbying effort, also said Wednesday that the issue might have been a focus of the Indo-US 2+2 dialogue which was planned for July 6. That was until the same newspaper reported Thursday that the talks have been postponed after India “refused to toe the Trump administration’s line on cutting down all oil supplies” from Iran.

The White House announced earlier this week that buyers of Iranian oil have until November to cut all oil purchases from the nation, or face sanctions.