The Pentagon is suspending flight training and other operational exercises for Saudi military students studying in the United States while American officials investigate last week’s deadly shooting at Naval Air Station Pensacola by a Saudi airman, defense officials said.

The move is part of a “safety stand-down” ordered by Deputy Secretary of Defense David L. Norquist under which the military will review how it screens foreign military students and grants them access to bases.

Flight training and the other exercises are being halted for the roughly 850 Saudi trainees in the United States pending the completion of the review, which could take a week or more, officials said. That means Saudi pilots, including several hundred studying at Naval Air Station Pensacola and other bases in the state, will be grounded for the time being.

Classroom training will continue after being suspended over the weekend.

The review is designed to strengthen vetting procedures for international military students so they align more closely with vetting procedures used for U.S. personnel, Norquist wrote in a memo Tuesday. It will cover roughly 5,000 international military students from more than 150 countries training on U.S. bases.

“As we reaffirm our commitment to these critical military partnerships, so must we assess the efficacy of our security procedures in light of the tragic loss of life on December 6, 2019, at Naval Air Station Pensacola,” Norquist wrote. “In doing so, we will make every effort to ensure the safety of all personnel and their families on U.S. military installations.”

The review is being led by Undersecretary of Defense for Intelligence Joseph Kernan, a retired Navy vice admiral.

Three young sailors were killed, and eight people were wounded Friday when a Saudi air force trainee opened fire in a classroom at the Pensacola base. The gunman, a Royal Saudi Air Force member named Ahmed Mohammed al-Shamrani, was fatally shot by a sheriff’s deputy responding to the attack.

The shooting immediately prompted questions from lawmakers about how the U.S. government scrutinizes candidates for military exchange programs. Sen. Rick Scott (R.-Fla.) called for a “full review” of the programs, and Sen. Marco Rubio (R.-Fla.) said the attack exposed “serious” flaws in the vetting process.

“There is no reason we should be providing state-of-the-art military training to people who wish us harm,” Scott said last week. “And most importantly, there is no reason to risk the safety and security of our American men and women in uniform.”

The United States has a long-standing military education and training partnership with Saudi Arabia. To date, the Pentagon has trained more than 28,000 Saudi students without serious incident, according to defense officials.

A Pentagon spokesman, Air Force Lt. Col. Uriah Orland, declined to comment on whether the military has documented any past concerns about individual Saudi military students in the United States, citing privacy and security concerns.

In response to the shooting, Orland said, Gen. Terrence O’Shaughnessy, the commander of Northern Command, directed all military installations and units to increase random security measures and told leaders to remind their workforce to report suspicious activity.

Meanwhile, the FBI was investigating the attack as an act of terrorism and trying to learn whether the gunman was part of a larger network. The bureau has not disclosed how Shamrani, 21, obtained the 9mm Glock handgun he used in the shooting but said it was lawfully purchased.

The Navy identified the sailors killed as 19-year-old Mohammed Sameh Haitham, 23-year-old Joshua Kaleb Watson, and 21-year-old Cameron Scott Walters. On Tuesday, Navy officials posthumously awarded them Wings of Gold for their bravery in trying to thwart the shooting.

Dan Lamothe contributed to this report.

Read more: