If Washington keeps siding out Ankara with the F-35 project, it will look out for similar-class jets, Turkish President warned the US counterpart, adding his country won’t give up the Russian-made S-400 air defense systems.Recep Tayyip Erdogan shared some details about a tête-à-tête he had with Donald Trump last week. The two tried to defuse tensions that mounted after the US excluded Turkey from the F-35 development program citing its purchase of the Russian-built S-400 systems.Now, speaking to members of his ruling AK Party, Erdogan said he had told Trump that if Washington maintained its “uncompromising stance” on the F-35s, Turkey would have to switch to other alternatives.Meanwhile, there will be no concessions in relation to buying the S-400 systems, some of which have already gone online in Turkey, despite Trump trying to persuade Erdogan to abandon the deal with Moscow.Last week, the Turkish leader told reporters that the US president’s proposal was “an infringement on our sovereign rights.”