US Defense Secretary Mark Esper says he is not prepared at this point to label as "terrorism" the attack at a US Navy base in Florida, where a Saudi airman is accused of killing three people.
"No, I can't say it's terrorism at this time," Esper told the Reagan National Defense Forum in California, adding he believed investigators needed to be allowed to do their work.
A group that monitors online extremism says the suspect appeared to have posted criticism of US wars and quoted slain al Qaeda leader Osama bin Laden on social media hours before the shooting spree.
The shooter - in the US for aviation training - killed three people and himself on Friday.
US Defense Secretary Mark Esper. Source: Getty Images AsiaPac
The shooter had hosted a dinner party earlier in the week where he and three others watched videos of mass shootings, a US official says.
One of the three students who attended the dinner party videotaped outside the building while the shooting was taking place at Naval Air Station Pensacola, says the US official, who had been briefed by federal authorities.
Two other Saudi students watched from a car, the official says.
Ten Saudi students are being held on the base on Saturday while several others are unaccounted for.
US officials had previously told The Associated Press they were investigating possible links to terrorism.
The investigation is "active and still very fluid," the FBI's Jacksonville, Florida, bureau said on Saturday.
The incident underscored the US' sometimes rocky relationship with Saudi Arabia, which is a key US ally in the Middle East, but has been accused of war crimes in Yemen and the murder of journalist Jamal Khashoggi last year.
Much to the consternation of a majority of lawmakers in Congress, the president has maintained tight relations with Saudi Arabia, despite the Kashoggi murder.
According to the SITE Intelligence Group, a Twitter account believed to have belonged to the shooter posted a letter a few hours before the attack, which blasted the United States for supporting Israel and "funding crimes against Muslims".
Pensacola Naval Air Station. Source: Getty Images
The now-suspended Twitter account has not been verified by the dpa.
SITE director Rita Katz said the account's posts suggest a "terrorist motive".
On Friday the governor of Florida, Ron DeSantis, said Saudi Arabia "needs to make things better for the victims and they're going to owe a debt here".
The incident comes two days after a sailor shot dead two workers at Joint Base Pearl Harbor-Hickam in Hawaii, before the shooter took his own life.
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