Congress took another step towards banning the delivery of F-35 stealth fighter jets to Turkey on Monday, after the House and Senate agreed a compromise text to a defence spending bill due to be enacted later in the summer.

The two chambers agreed to prohibit delivery of any F-35s to Turkey until the Pentagon submits a plan that assesses the impact of cutting Ankara from participation in the jet programme and the state of US-Turkey relations, due within 90 days of the text becoming law.

The report would also include an assessment of the operational and counter-intelligence risks posed to the F-35 should Turkey deploy the Russian S-400 air and missile defence system. Expert have warned for months that the Russian system would effectively be able to spy on the F-35, the flagship fighter jet bought by 14 Nato countries.