Twenty-one members of the Saudi army are being expelled from the United States after a cadet conducted a mass shooting at an air base last month.
The military is not accused of helping the 21-year-old Saudi Air Force lieutenant.
But U.S. Attorney General William Barr said it was discovered that the cadets had jihadist material and indecent images of children in their possession.
Three sailors died and eight were injured in the December 6 attack.
Training for Saudi military was suspended in the United States after the attack.
Barr said in a press conference on Monday that the shooting at the Pensacola Naval Air Station had been an “act of terrorism.”
He said he had asked Apple to unlock two iPhones that belonged to the gunman, who was killed by police in the attack. The gunman fired a bullet into a phone in an effort to destroy it, Barr said, but FBI investigators were able to restore the device.
“We have asked Apple for help in unlocking the shooter’s iPhones,” Barr said. “So far Apple has not given us any substantial help.”
Apple had provided the FBI iCloud data of the attacker’s online account, the New York Times reported, but declined to unlock the phone, saying it would undermine its own encryption software.
The technology firm has previously faced the FBI over requests for unlocking iPhones belonging to terrorism suspects. A similar crash in 2016 was resolved when the FBI found a way to unlock a phone belonging to a mass shooter in California without Apple’s help.
Barr said the initial reports that other Saudi cadets had filmed the attack while it was going on were inaccurate. The gunman had arrived only at the scene of the shooting, he said.
The attorney general said that 17 of the expelled cadets had terrorist material online. Fifteen, including some of the 17 who possessed terrorist material online, had indecent images of children, he added.
“While one of the people had a significant number of images, the rest had one of two images, in most cases posted in a chat room by another person or received on social media,” Barr said.
He said the 21 cadets were being discharged and returned home on Monday. The Saudi cadets, he said, had fully cooperated with the FBI investigation.
Barr also said that the Kingdom of Saudi Arabia had provided “full and total” support for the investigation. Saudi authorities had determined that the conduct of the cadets was “to become an officer of the Royal Air Force and the Royal Navy of Saudi Arabia,” said the attorney general.
He added that the expelled cadets had not been charged with any crime in the United States, but could be prosecuted in their country. There are more than 850 Saudi military cadets conducting training in the United States.
Investigators say the attacker, second lieutenant Mohammed Alshamrani, had shown videos of violence to his colleagues at a dinner before the attack. The 9mm gun he used was legally purchased.
When asked about the planned expulsions on Sunday, White House national security adviser Robert O’Brien told Fox News that the Pentagon had decided to expel Saudi cadets.
“Obviously, Pensacola showed that there were errors in the way we investigated,” O’Brien said.
“And I think by caution Secretary [of Defence Mark] Esper is taking these measures to protect our men and women of service. “
The Pensacola base has long offered aviation training to foreign military forces. Saudi pilots began training there in 1995, along with other personnel from Italy, Singapore and Germany.
After last month’s attack, the base commander said about 200 international students were enrolled in programs there. According to its website, the base employs more than 16,000 military and 7,400 civilians.