US President Barack Obama personally warned Turkish Prime Minster Recep Tayyip Erodgan that the US will not sell weapons to Turkey if it does not change its position towards Israel, the Financial Times reported on Monday.

The ultimatum is particularly important to Turkey, who was reportedly planning to buy American drone aircraft to attack Kurdish group PKK after the US pulls out of Iraq next year.

“The president has said to Erdogan that some of the actions that Turkey has taken have caused questions to be raised on the Hill [Congress] .?.?.?about whether we can have confidence in Turkey as an ally," an administration source told The Financial Times. "That means that some of the requests Turkey has made of us, for example in providing some of the weaponry that it would like to fight the PKK, will be harder for us to move through Congress.”

“They need to show that they take seriously American national security interests,” the administration official reportedly added. He also said Washington was looking at Turkish conduct and would then assess if there were “sufficient efforts that we can go forward with their request”.

Obama has called on Ankara to tone down its rhetoric about the IDF raid on the Turkish blockade-breaking ship, Mavi Marmara. Washington also criticized Turkey recently for voting against UN sanctions on Iran.