Turkish President Recep Tayyip Erdogan has said his government may have to “rethink” existing orders for Boeing airplanes worth about $10bn, in comments that add to the tension created by Turkey going ahead with the acquisition of S-400 advanced missile defence systems from Russia.

The US is kicking Turkey out of the development programme for the F-35 stealth fighter jet, and refusing to deliver F-35s to Ankara, in response to the S-400 move and is mulling the imposition of sanctions. Turkey has said it will hit back if sanctions are announced. In the meantime, it is clearly looking for other ways to put pressure on Washington in the row, with Erdogan’s Boeing comments sure to not go down well with US officials.

Referring to his meeting nearly a month ago with US counterpart Donald Trump at the G20 summit in Japan, Erdogan reportedly said: “I’ve told Mr Trump in Osaka that even if Turkey’s not buying Patriots [from US company Raytheon], it’s buying Boeings. We’re good customers. But if it goes on like this, we’ll have to rethink about this issue.”

Boeing has an order for 100 aircraft from Turkish Airlines, Turkey’s flagship carrier in which the state holds a 49% stake.

On July 25, US Secretary of State Mike Pompeo said Washington would like to see Turkey decline to make the S-400s operational, but Erdogan was cited as saying they will go operational in April.

The systems could expose the performance data of the F-35, the world’s most sophisticated and expensive fighter jet, the Pentagon says.