The US president has nominated Mark Esper as the US Secretary of Defense.

MojNews- Donald Trump has nominated Mark Esper to be the US Secretary of Defense , the White House said late Friday, as Washington navigates a spike in tensions with Iran.

The nomination of Esper, who was this week elevated to acting Pentagon chief from his post as Army Secretary, was announced hours after Trump revealed he had come close to authorizing a strike on Iran after it shot down an American drone.

There hasn't been a full defense secretary since the resignation of James Mattis in December last year after splits in the administration over Trump's sudden decision to remove US troops from Syria.

Esper, who must be confirmed by the Senate, is the third man to lead the Pentagon in six months.