A Saudi Air Force second lieutenant killed four people and wounded eight others on Friday in an unexplained shooting rampage at a US Navy base in Florida where he was training, US officials told Reuters.

Sheriff’s deputies responding to the early-morning incident shot and killed the gunman, who was armed with a handgun at the US Naval Station in Pensacola, Navy and local law enforcement officials said.

The shooting, which played out over two floors in a classroom building at the base, marked the second deadly shooting at a US military installation this week, following a similar incident at the joint Air Force and Naval base at Pearl Harbor on Wednesday.

FBI investigators, who were leading a probe into the shooting, declined to identify the gunman and said at an evening news conference they had not established a motive for the attack.

But US officials familiar with the case told Reuters on condition of anonymity that the suspect had been identified as Saudi Second Lieutenant Mohammed Saeed Alshamrani.

“There are many reports circulating but the FBI deals only in facts. As soon as we can we will share more,” Rachel Rojas, special agent in charge of the FBI’s Jacksonville office, told a news conference.

In addition to the two people slain, two sheriff’s deputies were injured in the attack, one shot in the arm, the other in the knee but both were expected to survive, officials said at an earlier news conference.

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