US forewarn Turkey not to buy Russian S-400 rocket system. Moving on with the deal will jeopardize the F-35 fighter jet buy and other future arms transfers, US says.

The State Department made the remarks on a day when the head of US European Command spoke to politicians on Capitol Hill and said Turkey should reconsider its plan to buy the S-400 from Russia this year.

"We've clearly warned Turkey that its potential acquisition of the S-400 will result in a reassessment of Turkey's participation in the F-35 programme, and risk other potential future arms transfer to Turkey," said deputy spokesman Robert Palladino on Tuesday, Aljazeera reports.

The US agreed to sell 100 of its latest fifth-generation F-35 fighters to Turkey and has so far delivered two of the aircraft. But Congress last year ordered a delay in future deliveries.

The act would also ban the transfer of rights to F-35. Among the reasons for the move is the threat that Turkey might share the data on F-35 Lightning II following its purchase of the Russian S-400 surface to air missile system. Turkey responded by promising to buy Russian made Sukhoi Su-57 instead of the US fighters, RT reports.

To start with, we do not have the data for F-35, leave along the Russian Sukhoi Su-57, although the level of transparency for foreign military hardware has traditionally been higher than in Russia. For example, it does not make sense to compare the speed parameters of operational and prototype aircraft.

F-35 rocket- Military Watch says the two fighters are significantly different. Lockheed Martin F-35 is a light aircraft with lower than average manoeuvrability. F-35 Lightning II is a family of single-seat, single-engine, all-weather stealth multirole fighters. The fifth-generation combat aircraft is designed to perform ground-attack and air-superiority missions

The Su-57- by contrast was designed as a heavy air superiority platform and is more capable in an air-to-air combat role, adds Military Watch. The analysis gives an advantage to the Sukhoi Su-57 in its speed, altitude, sensors, missile carriage, engagement range, and manoeuvrability. Su-57 retains a considerable advantage over the F-35 in the air, according to Military Watch. But there is a big question: is the comparison legitimate in the absence of real data?  Lockheed Martin F-35 is a light aircraft with lower than average manoeuvrability.

Some sources compare both jet fighter almost equally. Turkey will say its final decision to buy which aircraft. 

Gozel Hashimova