As the Naval Air Station in Pensacola, Florida, reopens after Friday’s deadly shooting, the city’s mayor said the city is under a cyberattack.

Mayor Grover Robinson said Monday morning almost all computer communication systems at City Hall are down, according to the Pensacola News Journal. It is unknown whether the cyberattack is related to the shooting.

Police and fire departments have not been affected, but online payment systems for Pensacola Energy and city sanitation are not working. Robinson said the attack began early Saturday.

On Sunday, federal officials characterized their investigation as a terrorism inquiry into the shooting. Mohammed Alshamrani, 21, a 2nd lieutenant in the Royal Saudi Air Force, allegedly opened fire Friday morning in one of the base's classrooms, killing three sailors, one of whom was from Georgia.

Responding officers shot and killed Alshamrani. Among the eight other people injured were two deputies who initially confronted the gunman.

On Monday, U.S. Sen. Rick Scott (R-Fla.) said the U.S. should suspend military programs to train foreign nationals on American soil until federal officials completed their investigations.

»RELATED: 3 dead sailors, including one from Georgia, ID'd in Pensacola shooting

New evidence emerged over the weekend Alshamrani, a Saudi trainee, filed a formal complaint earlier this year against one of his instructors, who left him “infuriated” in class by tagging him with a derogatory nickname.

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The complaint, quoted in a communication circulated among people connected to the flight training, said the instructor referred to Alshamrani as “Porn Stash” in front of about 10 other aviation students, embarrassing and angering him.

»RELATED: FBI thinks Pensacola base shooting was act of terrorism

“I was infuriated as to why he would say that in front of the class,” the Saudi trainee wrote in his complaint, as quoted in the summary. The document was reviewed by The New York Times and authenticated by a person who spoke with Alshamrani shortly after the incident.

Alshamrani had apparently gone on Twitter shortly before the shooting to blast U.S. support of Israel and accuse America of being anti-Muslim, a U.S. official said Sunday.

Investigators are also trying to establish whether Alshamrani, who was undergoing flight training at Pensacola, acted alone or was part of a larger plot.

Family members and others identified the three dead as Joshua Kaleb Watson, a 23-year-old recent graduate of the U.S. Naval Academy; Airman Mohammed Sameh Haitham, 19, of St. Petersburg, Florida, who joined the Navy after graduating from high school last year; and Airman Apprentice Cameron Scott Walters, 21, of Richmond Hill, Georgia. All three were students at Naval Aviation Schools Command.

In this Nov. 22, 2019 photo provided by the Walters family, Cameron Walters, center in Navy uniform, poses for a photo with his sisters, Lily Walters, left, and Shania Walters, right, and his father, Shane Walters, far right. 

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Credit: Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. Copyright 2019 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

President Donald Trump declined to say whether the shooting was terrorism-related but said Saturday that he would review policies governing foreign military training in the U.S.

The U.S. has long had a robust training program for Saudis, providing assistance in the U.S. and in the kingdom. More than 850 Saudis are in the United States for various training activities. They are among more than 5,000 foreign students from 153 countries in the U.S. going through military training.