The Saudi Air Force trainee who killed three and injured eight when he opened fire at a naval base in Florida on Friday assailed the United States as 'a nation of evil' just before his shooting rampage, AFP reports.

The man, identified as Mohammed Saeed Alshamrani, opened fire inside a classroom at Naval Air Station in Pensacola early Friday morning. Police quickly responded to the scene and he was shot dead.

Alshamrani was a second lieutenant attending the aviation school at the base. The Pentagon say his training with the US military began in August 2016, and was due to finish in August 2020.

On Friday evening, the SITE Intelligence Group, which monitors jihadist media, claimed they had tracked a Twitter account belonging to Alshamrani which featured a disturbing manifesto written just hours before the shooting.

'I'm against evil, and America as a whole has turned into a nation of evil,' it read.

'I'm not against you for just being American, I don't hate you because your freedoms, I hate you because every day you supporting, funding and committing crimes not only against Muslims but also humanity,' Alshamrani wrote.

ABC News reported that investigators were working to determine if if the tweet was in fact written by the shooter.

The Twitter account that posted the manifesto - which also condemned US support for Israel and included a quote from Al-Qaeda's deceased leader, the Saudi Osama bin Laden - has now been suspended.

The suspected gunman, Saudi second lieutenant Mohammed Saeed Alshamrani,reportedly condemned the US as a 'nation of evil' before going on his shooting rampage at Naval Air Station in Pensacola early Friday morning (pictured by NBC 6 South Florida)

Part of the suspect's alleged manifesto, which was published on Twitter shortly before the attack

Meanwhile six other Saudi nationals were arrested near the base shortly after the attack, as investigators began to probe a terror link.

Three of the six were seen filming the entire incident as it unfolded, a source told The New York Times on Friday evening.

No officials have yet stated whether any of them were students inside the classroom where the shooting occurred.

The FBI addressed the public at 8pm local time, and said that they were still in the process of an 'active' investigation that would be continuing '24/7'.

They did not release the names of any of the victims.

Military from around the globe attend the Naval Air Station in Pensacola, which is the home of the Navy's revered Blue Angels aerial demonstration team.

The FBI addressed the public at 8pm local time, and said that they were still in the process of an 'active' investigation that would be continuing '24/7'

Military from around the globe attend the Naval Air Station in Pensacola, which is the home of the Navy's revered Blue Angels aerial demonstration team. The station is pictured after the shooting on Friday

President Donald Trump this afternoon tweeted that he spoke on the phone with Saudi Arabia's King Salman, who he said expressed 'sincere condolences' to those impacted by the shooting.

Trump added that King Salman informed him the Saudi people love Americans and 'are greatly angered by the barbaric actions of the shooter...'

The shooter opened fire in a classroom building shortly before 7am Friday. The attack left four people dead, including the assailant, and eight others wounded.

During an afternoon press briefing, Florida Governor Ron DeSantis confirmed the shooter was from Saudi Arabia, which has long relied on the US to train it military officers.

'There's 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 told reporters.

'Obviously the government of Saudi Arabia needs to make things better for these victims. And I think they are going to owe a debt here given that this is one of their individuals.'

Of the 19 men involved in the September 11 attacks, 15 were Saudi and some of them attended flight school in Florida.

The gunman opened fire at Naval Air Station Pensacola Friday morning, killing three people and injuring eight others before being shot dead by sheriff's deputies

During an afternoon press briefing, Florida Governor Ron DeSantis confirmed the shooter was from Saudi Arabia, which has long relied on the US to train it military officers

Heavy police presence was reported at the scene of the shooting Friday morning

In recent weeks, 18 naval aviators and two aircrew members from the Royal Saudi Naval Forces were training with the US Navy, including at Pensacola, according to a November 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 program that offers training to US allies, known as the Naval Education and Training Security Assistance Field Activity.

A person familiar with the program 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.

Officials announced Friday morning that the shooter was killed by two Escambia County Sheriff's deputies, who were injured during the exchange.

Three of the fatally injured people were pronounced dead at the scene and the fourth passed away at the hospital.

An ambulance is seen arriving at the scene of the mass shooting at NAS Pensacola

An armored vehicle is pictured on the scene during Friday's shooting that claimed three innocent lives

Twenty 'hand-picked' Saudi airmen training at Pensacola are among the 62,700 foreign military personnel the US trains each year In the 2018 fiscal year, some 62,700 foreign military students from 155 countries participated in U.S.-run training, the total cost of which was approximately $776.3 million, according to DoD records. Among them is a contingent Saudis who recently arrived at Naval Air Station Pensacola. In recent weeks, 18 naval aviators and two aircrew members from the Royal Saudi Naval Forces were training with the U.S. Navy, including a stint at Pensacola, according to a November 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 program that offers training to U.S. allies, known as the Naval Education and Training Security Assistance Field Activity. A person familiar with the program 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. Saudi Arabia, a major purchaser of U.S. arms, accounts for a massive portion of America's spending on foreign military training. In the 2018 fiscal year, the U.S. trained 1,753 Saudi military members at an estimated cost of $120,903,786, according to DoD records. For fiscal year 2019, the State Department planned to train roughly 3,150 Saudis in the U.S. -Keith Griffith for DailyMail.com and Reuters Advertisement

'This was an act of terrorism,' Rep Matt Gaetz, a Republican representing Pensacola, told the station WEAR.

The congressman said the investigation into the shooting has been handed over from NCIS to the FBI, signaling that it was 'not an act of workplace violence,' but rather an act of terror.

After news broke that the suspect was a Saudi national, Donald Trump tweeted that 'King Salman of Saudi Arabia just called to express his sincere condolences and give his sympathies to the families and friends of the warriors who were killed and wounded in the attack that took place in Pensacola, Florida.'

The President continued: '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.'

Escambia County Sheriff David Morgan said a 911 call was received at 6.51am central time reporting an active shooter on base.

Two deputies confronted the gunman inside a classroom building and exchanged gunfire, killing the perpetrator.

It has since been revealed that the gunman was armed with a handgun.

One of the officers suffered a gunshot wound to the arm, while the other was shot in the knee and underwent surgery.

Morgan said both deputies are expected to recover.

In total, eight people were taken to Baptist Health Care in Pensacola, one of whom later died.

Law enforcement and US Navy officials declined to release any information concerning the identities of the shooter and the victims pending the notification of next of kin.

Commanding officer Timothy Kinsella said the base's security forces first responded to the shooting before outside police agencies arrived.

The facility, which is used for training and made up mostly of classrooms, 'is shut down until further notice,' he said.

Florida State Troopers block traffic over the Bayou Grande Bridge leading to the Pensacola Naval Air Station

This map shows the location of the sprawling Naval Air Station Pensacola

Sheriff Morgan said the crime scene was spread over two floors, which were left littered with spent shell casings.

'Walking through the crime scene was like being on the set of a movie,' he revealed.

Federal agencies are investigating, authorities said, including the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives.

St. John's Catholic School, located directly outside the air station, was placed on lockdown as a precaution.

Eight people were taken to Baptist Health Care in Pensacola from the site of the shooting

A Facebook message from NAS Pensacola this morning confirmed an active shooter situation

PREVIOUS MASS SHOOTINGS AT US MILITARY FACILITIES While mass shootings in the United States are common, those at military facilities are rare. In July 2015, Mohammad Youssuf Abdulazeez carried out an attack at two military installations in Tennessee that killed four Marines and a sailor, with the FBI concluding that the violence was inspired by a 'foreign terrorist group.' Two years earlier, Aaron Alexis killed 12 people and wounded eight others at the Washington Navy Yard, just two miles (three kilometers) from the US Capitol building, before being shot dead by officers. Four years before that, Major Nidal Hasan, a US Army psychiatrist, killed 13 people and wounded more than 30 others at Fort Hood. He was considered a 'lone wolf' who supported terror network Al-Qaeda. Supporters of tighter gun laws seized on the latest shooting. 'Our veterans and active-duty military put their lives on the line to protect us overseas -- they shouldn't have to be terrorized by gun violence at home,' Cindy Martin, a volunteer with the Florida chapter of Moms Demand Action whose daughter works at the naval base, said in a statement. Source: AFP Advertisement

NAS Pensacola employs more than 16,000 military and 7,400 civilian personnel, according to its website.

One of the Navy's most historic and storied bases, it sprawls along the waterfront southwest of downtown Pensacola and dominates the economy of the surrounding area.

It's home to the Blue Angels flight demonstration team, and includes the National Naval Aviation Museum, a popular regional tourist attraction.

The shooting in Pensacola comes less than 48 hours after an active duty US sailor opened fire at Pearl Harbor's naval shipyard in Hawaii, killing two civilian workers and injuring a third, before taking his own life.