US lawmakers, meanwhile, called for the Saudi training program to be halted pending the investigation’s outcome.

WASHINGTON, United States (AFP) — Key US lawmakers called Sunday for a halt to a Saudi military training program after a shooting rampage at a naval base in Florida in which a Saudi officer killed three American sailors.

US Defense Secretary Mark Esper said he has ordered a review of vetting procedures while defending the training program that brought Mohammed Alshamrani to Pensacola Naval Air Station.

Alshamrani, a 21-year-old second lieutenant in the Saudi Royal Air Force, opened fire in a classroom on Friday, killing the three sailors and wounding eight other people before being shot dead by police.

Alshamrani, who was armed with a lawfully purchased Glock 9mm handgun, was reported to have posted a manifesto on Twitter before the shooting denouncing America as “a nation of evil.”

The FBI said Sunday they were investigating with the “presumption” it was an act of terrorism, as in most active shooter probes, but had yet to make a final determination.

White House National Security Advisor Robert O’Brien went further, however, saying: “To me, it appears to be a terrorist attack.”

“We’ll have to see what the FBI investigation shows,” O’Brien added, on CBS’s “Face the Nation.”

The FBI’s main goal, special agent-in-charge Rachel Rojas told a news conference, is to confirm whether Alshamrani “acted alone or was he a part of a larger network.”

“We currently assess there was one gunman who perpetrated this attack and no arrests have been made in this case,” she said.