The FBI said Sunday that it will "work with the presumption that this was an act of terrorism" after aleft . The gunman has been identified as Mohammed Saeed Alshamrani, 21, a Saudi national who was a naval student at Naval Air Station Pensacola.
"As we speak, members of the FBI join terrorism task force and counterterrorism division are working tirelessly to discern if any possible ideology may have been a factor in this attack, but they are working alongside members of our criminal team as well so we are all on the same page no matter which direction our investigation takes," Rachel Rojas, the FBI special agent in charge of the investigation, said at a press conference Sunday.
The FBI also confirmed the weapon used in the attack was a Glock 45 9mm that was purchased lawfully.
The FBI said it had uncovered digital evidence, including base security surveillance and cell phone videos taken by a bystander from outside the building. The bystander began filming after the attack had started and first responders arrived.
National Security Adviser Robert O'Brien told "" on Sunday morning that the shooting "appears to be a terrorist attack."
"I don't want to prejudge the investigation, but it appears that this may be someone that was radicalized, whether it was here or it's unclear if he's got any other ties to other organizations," O'Brien said.
All international students at the Pensacola base have been accounted for, there have been no arrests, and the community is under no immediate threat, Rojas said Sunday. A Saudi commanding officer has ordered all students from the country to remain at one location at the base, officials also said at the news conference.
Additionally, authorities believe the gunman made social media posts in which he talked about U.S. support for Israel and charged that Americans are anti-Muslim, a U.S. official told The Associated Press on Sunday. Investigators also believe the gunman visited New York City, including Rockefeller Center, days before the shooting and are working to determine the purpose of the trip, said the official, who was not authorized to discuss the matter publicly and spoke to the AP on condition of anonymity.
The FBI and others had said they were trying to determine whether Alshamrani, 21, of the Royal Saudi Air Force, acted alone. Alshamrani was a flight student at Pensacola, where members of foreign militaries are routinely trained by the U.S.
Earlier in the week of the shooting, Alshamrani hosted a dinner party where he and three others watched videos of mass shootings, another U.S. official told the AP on Saturday.
The U.S. has sought the assistance of Saudi officials as they try to piece together information about the gunman and his motive.
Alshamrani opened fire inside a classroom at the base, killing three people and wounding two sheriff's deputies, one in the arm and one in the knee, before one of the deputies killed him. Eight others were also hurt. Both deputies were expected to survive.
The official who spoke Saturday said one of the three students who attended the dinner party hosted by the attacker recorded video outside the classroom building while the shooting was taking place. Two other Saudi students watched from a car, the official said.
Ten Saudi students were being held on the base Saturday as part of the investigation, the official said.
President Trump declined to say whether the shooting was terrorism-related but said Saturday that he would review policies governing foreign military training in the U.S.
The U.S. has long had a robust training program for Saudis, providing assistance in the U.S. and in the kingdom. More than 850 Saudis are in the United States for various training activities. They are among more than 5,000 foreign students from 153 countries in the U.S. going through military training.
"This has been done for many decades," Trump said. "I guess we're going to have to look into the whole procedure. We'll start that immediately."
Family members and others identified the three dead as Joshua Kaleb Watson, a 23-year-old recent graduate of the U.S. Naval Academy; Airman Mohammed Sameh Haitham, 19, of St. Petersburg, Florida, who joined the Navy after graduating from high school last year; and Airman Apprentice Cameron Scott Walters, 21, of Richmond Hill, Georgia. All three were students at Naval Aviation Schools Command.