ANKARA (Reuters) - F-16 warplanes will fly over the capital Ankara on Monday to test Syria's S-400 missile defense system, Turkish media reported.

This development comes despite Washington's continued pressure on Turkey to abandon the Russian system.

Ankara's purchase of the Russian system has been a key factor in straining relations with Washington, which says the system is incompatible with NATO defenses and poses a threat to the US F-35 fighter jet capable of hiding radars.

Ankara's governor's office announced on Sunday that F-16 fighter jets and other Turkish Air Force fighter jets would fly low and high altitudes over Ankara on Monday and Tuesday to test a "draft air defense system."

CNN Turk and other media said the flights were specifically designed to test the S400 radar system.

Turkey began taking over the defense system in July but has not yet entered operations.

Last Thursday, a senior State Department official said Turkey should "get rid of" Russia's S400 system.

The comments came after US President Donald Trump hosted his Turkish counterpart Recep Tayyip Erdogan at the White House earlier this month.

Trump called the meeting "wonderful." But it is not clear whether the NATO partner countries have made any progress on the S400 issue.

Erdogan later said US pressure to abandon the S-400 system would infringe on his country's sovereign rights.

The United States has suspended Turkey's participation in the F-35 fighter planes to punish it for buying the Russian system. It has threatened sanctions for the deal, but has yet to do so.