The father of Orlando shooter Omar Mateen was spotted sitting behind Hillary Clinton at a campaign rally in Florida.

Seddique Mateen, whose son carried out the deadliest mass shooting in US history in June at the Pulse nightclub, looked on as Clinton began her speech on Monday in Kissimmee recalling the terror attack.

“Bill and I were in Orlando about two weeks ago, and we had a chance to sit down with Mayor Dyer, other elected officials, members of the clergy, of the brave police officers who rushed into the Pulse nightclub massacre to save lives,” Clinton said, according to a transcript released by her presidential campaign.

“I just have to tell you how grateful I am for the leadership and the people of Orlando and Central Florida for your love and compassion. And I know how many people, loved ones and friends, are still grieving. And I want them to know that we will be with you. We will be with you as you rebuild your lives, as you rebuild hope for the future, because we can’t ever let that kind of hatred and violence break the spirit, break the soul, of any place in America.”

Mateen was spotted by local affiliate NewsChannel 5 WPTV of West Palm Beach.

“We’ve been cooperating with the federal government, and that’s about it,” the father told the local station in a brief interview. “Thank you.”

In a statement to the press, the Clinton campaign said: “The rally was a 3,000-person, open-door event for the public. This individual wasn’t invited as a guest and the campaign was unaware of his attendance until after the event.”

Later, in another interview with the station, the father endorsed Clinton.

“Hillary Clinton is good for United States versus Donald Trump, who has no solutions,” the father of the gunman said.

He added: “I … wish that my son joined the Army and fought ISIS. That would be much better.”

The Clinton campaign did not respond to a request from The Post asking whether it accepted Mateen’s endorsement.