The FBI is investigating the fatal shooting at a Naval base in Florida as an act of terrorism, a special agent said Sunday.
Rachel Rojas, special agent in charge of the FBI's Jacksonville office, told a news conference Sunday that the investigation was taking place under the "presumption" it was an act of terrorism, but that the gunman had likely acted alone.
"We currently assess there was one gunman who perpetrated this attack and no arrests have been made in this case," she said.
The FBI officially identified the shooter who killed three people as Mohammed Alshamrani, a 21-year-old second lieutenant in the Royal Saudi Air Force who was a student naval flight officer at the Naval Aviation Schools Command at Naval Air Station Pensacola.
Authorities are still searching for a motive for the rampage which also injured eight others.
"We are looking very hard at uncovering his motive and I would ask for patience so we can get this right," Rojas said.
U.S. Defense Secretary Mark Esper said Sunday that he has instructed the armed forces to review their screening processes of foreign soldiers following the deadly shooting.
Speaking on Fox News Sunday, Esper said one of the first things he did following the killing of three people Friday was he "asked that we begin a review of what "our screening procedures are with regard to foreign nationals coming to the United States".
The victims were also students at the flight school. They have been identified as Ensign Joshua Kaleb Watson, 23, from Coffee, Alabama; Airman Mohammed Sameh Haitham, 19, from St. Petersburg, Florida; and Airman Apprentice Cameron Scott Walters, 21, from Richmond Hill, Georgia.
"The sorrow from the tragic event on NAS Pensacola will have a lasting impact on our installation and community," Captain Tim Kinsella, the commanding officer of the naval base said in a statement.
The shooter, who was also killed in the incident, is reported to have hosted a dinner party earlier in the week where he showed videos of mass U.S. shootings to his guests, according to media reports. At least one of his guests is reported to have videotaped Friday's massacre. Several Saudi students are being held for questioning.
Before the pilot opened fire at the base, he tweeted a will and quoted Osama bin Laden in justifying his actions, according to the SITE Intelligence Group, which translates jihadist threats and communications.
In the Twitter post, he said America "has turned into a nation of evil." He condemned the U.S. for its support of Israel and its invasion of Muslim countries and many other countries. Using a bin Laden quote, he also said that the security of the U.S. and Muslims is a "shared destiny." He added, "You will not be safe until we live it as reality in pleastain [sic], and American troops get out of our lands."
Guns are not permitted at the Pensacola Naval Air Station, but Escambia County Sheriff David Morgan said the shooter managed to get a handgun onto the base before targeting individuals at one of the buildings. Officials said the rampage ended when a sheriff's deputy cornered and shot the suspect in a classroom.
U.S. President Donald Trump tweeted Friday that he had been in contact with Saudi King Salman, who offered condolences.
"The King said that the Saudi people are greatly angered by the barbaric actions of the shooter," Trump said.
In a statement, Salman called the shooting a "heinous crime" and said he expressed his sorrow over the attack in his phone call with Trump. The king said he has directed Saudi security services to cooperate with American agencies to uncover information that will help determine the cause of the "horrific attack."
The shooting at the Pensacola Naval Air Station is the second deadly shooting at a U.S. naval facility in the week.
A U.S. sailor shot three civilians at a base in Pearl Harbor, Hawaii, Wednesday, killing two of them before committing suicide.