The FBI agent who fired several shots at a fellow passenger aboard a Red Line Metro train this week did so after a “verbal exchange” between the two, transit police officials said Friday.

The shooting left the passenger hospitalized with gunshot wounds, the officials said.

At least two investigations are underway about the shooting, which erupted about 6:40 a.m. Tuesday as a Red Line train heading south approached the Medical Center station in Montgomery County.

The FBI is conducting one probe. The other is a joint investigation by the Metro Transit Police Department — the main law enforcement agency for the train system — and the Montgomery County State’s Attorney’s Office.

“This matter is an active criminal investigation, and we are working closely with the Montgomery County, Maryland State’s Attorney’s Office,” Metro Transit Police Chief Ronald A. Pavlik Jr. said in a news release. “We are continuing to collect and process evidence, including conducting interviews, to determine what happened on that train.”

Investigators have reviewed video recordings from rail car and station cameras. They have also spoken to other passengers and Metro employees.

The information released Friday did not say what the verbal altercation was about, what sparked it, or whether there was any physical contact before the shooting.

The transit agency also released a preliminary timeline of events. The agency said the incident started after a man approached the FBI agent as the train neared Medical Center station. After a verbal exchange, the agent fired multiple shots, hitting the passenger, Metro said.

The agent and the passenger then got off the train and onto the platform of Medical Center at 6:41 a.m.

The news release said that “another passenger” called 911 about the shooting, but said nothing about anyone else calling for help. The passenger who called 911 also used an emergency call button on the platform at Medical Center to summon the station manager.

At 6:44, the station manager flagged the rail operations control center to a shooting victim on the platform. The control center then radioed the train operator, who had not known about the shooting. Police and medics arrived, and Metro Transit Police were sent to intercept the train that wound up in Tenleytown at 6:49 a.m. Metro said the man was taken from the Medical Center station to a hospital at 7:06 a.m.

Pavlik said he expected to provide another update Monday.

The FBI’s National Press Office declined to answer questions about the shooting and the agent on Friday. The agency has released little information about the matter, other than a statement on Tuesday that an agent had been “involved” in a shooting on the Red Line, which resulted in one person being wounded and taken to a hospital.