Investigators looking into the shooting at the naval air station in Pensacola that left four people, including the assailant, dead, are working under the presumption that it was an "act of terrorism," a US Federal Bureau of Investigation (FBI) special agent said on Sunday (local time).
The assailant, identified as 21-year-old Mohammed Alshamr, was a second lieutenant in the Royal Saudi Air Force and a student naval flight officer. His motive for the attack still remains undetermined.
FBI Special Agent in Charge Rachel Rojas said that the investigators are working with "the presumption that this was an act of terrorism," as they do in most similar cases, adding that it allows agents to take advantage of certain "investigative techniques," CNN reported.
"Members of the FBI's Joint Terrorism Task Force and the FBI's Counterterrorism Division are working tirelessly to discern if any possible ideology that may have been a factor in this attack," she said
White House National Security Advisor Robert O'Brien also said on Sunday that the incident "appears to be a terrorist attack."
A source familiar with the investigation had told the New York Times on Saturday that the attacker had watched the videos of mass-shooting at a dinner party the night before he went on a shooting spree.
Alshamr, who was killed by a sheriff's deputy while responding to the attack, initially entered the US in 2017, when his training began at the Pensacola site, Pentagon officials have said.
After his initial arrival in the country, he attended language school at Lackland Air Force Base in San Antonio, Texas, and took classes in English and aviation, the officials added.
He would travel back home to Saudi Arabia during school breaks, but after his return in February, friends and colleagues noticed that he had become more religious, the officials added.
Saudis have received training at the Pensacola site since the 1970s. As of Friday, there were 852 Saudis in the US for Pentagon-sponsored training related to security cooperation, representing 16 per cent of the 5,181 students from 153 countries in these programs, Defense Department spokesman Chris Garver said, as cited by Washington Post.
( With inputs from ANI )