PENSACOLA, Florida (REUTERS) - A member of the Saudi Air Force visiting the United States for military training was the suspect in a shooting that killed four people and injured eight at a US Navy base in Florida on Friday (Dec 6), the state governor and other officials said.

The shooter was killed by sheriff's deputies responding to the dawn incident at Naval Air Station Pensacola, the Navy and local sheriff's office said, the second deadly shooting at a US military installation this week.

Florida Governor Ron DeSantis said the suspect was a Saudi national attending training at the base as part of a longstanding Navy programme open to US allies.

The motive for the violence was under investigation.

"There is obviously going to be a lot of questions about this individual being a foreign national, being a part of the Saudi Air Force and then to be here training on our soil," DeSantis said at a news conference.

"The government of Saudi Arabia needs to make things better for these victims. They are going to owe a debt here, given that this was one of their individuals."

US President Donald Trump said Saudi Arabia's King Salman called him to offer condolences and sympathy to the victims.

"The King said that the Saudi people are greatly angered by the barbaric actions of the shooter, and that this person in no way shape or form represents the feelings of the Saudi people who love the American people," Trump wrote on Twitter.

The suspect used a handgun in the attack, which played out over two floors in classroom building at a base whose main function is training.

"Walking through the crime scene was like being on the set of a movie," Sheriff David Morgan said.

The first reports of an "active shooter" on the base came through to the Escambia County sheriff's office at about 6.51am, officials said.

A few minutes later, a sheriff's deputy fatally shot the shooter in a classroom on the base, Morgan said.

The FBI said it was the lead investigative agency on the incident.

The suspected shooter was Second-Lieutenant Mohammed Saeed Alshamrani, according to two US officials familiar with the case who spoke on condition of anonymity.

The Saudi government was expected to launch its own investigation, and the US government intended to share its finding with Riyadh, one of the people familiar with the case said.

TRAINEES ARE HIGHLY VETTED

In recent weeks, 18 naval aviators and two aircrew members from the Royal Saudi Naval Forces were training with the US Navy, including a stint at Pensacola, according to a Nov 15 press release from the Navy.

It was not clear if the suspected shooter was part of that delegation.

The delegation came under a Navy programme that offers training to US allies, known as the Naval Education and Training Security Assistance Field Activity.

A person familiar with the programme said that Saudi Air Force officers selected for military training in the United States are intensely vetted by both countries.

The Saudi personnel are "hand-picked" by their military and often come from elite families, the person said, speaking on condition of anonymity because they did not have permission to speak to a reporter. Trainees must speak excellent English, the person said.

Saudi Arabia's embassy in Washington did not respond to questions.

Two sheriff's deputies were injured, one shot in the arm, the other in the knee, but both were expected to survive, officials said at the news conference.

Eight people were taken to Baptist Hospital for treatment, hospital spokesman Kathy Bowers said.

Sheriff's officials said one of the three victims died after being taken to the hospital, but it was unclear whether that victim was one of the eight who arrived at Baptist. Bowers declined to say.

While military bases house the nation's most powerful armaments, military personnel normally are restricted from carrying weapons on base unless they are part of their daily duties. Nonetheless US military bases have seen deadly mass shootings before, including one in Ford Hood, Texas, in 2009 that left 13 dead and one at the Washington Navy Yard in 2013 that killed 12.

On Wednesday, a sailor shot three civilians at the historic Pearl Harbor military base in Hawaii, killing two of them before taking his own life.

The Pensacola base, near Florida's border with Alabama, is a major training site for the Navy and home to its aerobatic flight demonstration squadron, the Blue Angels. The base employs more than about 16,000 military and 7,400 civilian personnel, according to its website.

US Defence Secretary Mark Esper said in a statement he was considering several steps to ensure the security of military installations after the shootings. He did not elaborate.

Pensacola Mayor Grover Robinson told reporters the base is"an incredibly important part of our community".

"We're a military town," he said. "Our hearts and prayers are connected to all of those that serve us every day."