Authorities are trying to determine whether a Saudi Airman acted alone when he opened fire at Pensacola Naval Air Station on Friday, killing 3 US service members.
Mohammed Alshamrani, a Saudi Air Force lieutenant, is believed to have tweeted about his hatred of Americans a short time before the shooting.
The tweets were deleted, but have been recovered. One says about Americans: "I hate you because every day you (are) supporting, funding and committing crimes not only against Muslims but also humanity."
The dead victims have been identified as 23-year-old Ensign Joshua Kaleb Watson, 19-year-old Airman Mohammed Sameh Haitham and 21-year-old Airman Apprentice Cameron Scott Walters.
Alshamrani used a Glock 9 mm pistol purchased legally in Florida under a federal loophole that allows representatives of so-called friendly nations to buy guns.
Florida Gov. Ron DeSantis said he supports the Second Amendment but that it does not apply to Saudis.
"You have foreign military personnel coming to our base. They should not be doing that if they hate our country," DeSantis said.
In the days before the shooting, Alshamrani reportedly showed videos of mass shootings at his home.
Secretary of Defense Mark Esper says he's ordered a review of the foreign nationals exchange program and base security.
"Yesterday I directed that we look at all of our security precautions across the services at our bases and facilities and installations to make sure we have the proper amount of security to protect our service members and their families," Esper said.
Meanwhile, 10 other Saudi nationals are restricted to an area on base and the FBI is trying to determine if others were involved. One Saudi was detained at the scene of the attack after apparently taking videos on a phone.
FBI Special Agent Rachel Rojas told reporters, "Our main goal right is to confirm whether he acted alone or was he a part of a larger network."
President Trump said the Saudis will cooperate and compensate the victim's families.
"I spoke with a Kingdom of Saudi Arabia. They are devastated in Saudi Arabia we're finding out what took place, whether it's one person or a number of people," Trump said.
Florida Rep. Matt Gaetz (R-FL) said the Saudis better cooperate. He told ABC's This Week program, "We expect Saudi intelligence to work with our government, to find the people accountable and hold them responsible And I was given every assurance from the ambassador that that would occur."
Investigators also believe the gunman visited New York City days before the shooting and are working to determine the purpose of the trip.