Defense Secretary nominee Mark Esper testifies before a Senate Armed Services Committee hearing on his nomination in Washington, U.S. July 16, 2019. REUTERS/Erin Scott

WASHINGTON (Reuters) - U.S. President Donald Trump’s nominee to become the next secretary of defense re-stated that Turkey cannot have the F-35 advanced stealth fighter jet and Russia’s S-400 air defense system, which Moscow started delivering last week.

“The policy that I have communicated to my counterpart, if confirmed, (Turkey’s) defense minister is that you can either have the S-400 or you can have the F-35, you cannot have both,” said Army Secretary Mark Esper, testifying at his confirmation hearing on Tuesday before the Senate Armed Services Committee.

“Acquisition of the S-400 fundamentally undermines the capabilities of the F-35 and our ability to retain that over -match in the skies going forward.”