ANKARA, Nov. 19 (Xinhua) -- If the U.S. stance on delivery of F-35 fighter jets does not change, Turkey would be forced to "look elsewhere" to meet its defense necessities, Turkish President Recep Tayyip Erdogan said Tuesday.

"If the current disagreement on F-35 fighter jets continues, Turkey must look elsewhere to meet its medium-term needs," Erdogan said while addressing his party members at the parliament.

The Turkish president was referring to his meeting last week with U.S. President Donald Trump in Washington.

Turkey would not step back from its deployment of the Russian S-400 air defense systems, Erdogan said.

"There are efforts to turn the S-400s into a key problem of the bilateral matters. We have agreed (with Trump) to seek ways to resolve the S-400 issue through our officials we have instructed," he stated.

Turkey's procurement of the Russian S-400 missile defense systems prompted the Trump administration to suspend Ankara from the F-35 fifth-generation joint strike fighter program in July.

Russia has expressed its readiness for a potential agreement with Turkey on the sale of Russian Su-35 or Su-57 aircraft.