The victims included transportation authority employees.
Sergeant Davis said that the shooting was reported at about 6:30 a.m. local time, and that the victims included employees of the V.T.A., but he did not have a number. He said he did not know what kind of weapon was used or the motive.
Earlier on Wednesday, Mr. Liccardo, the mayor, said on Twitter that the shooting “has left several people being treated, but the situation is still being assessed.”
“The shooter is no longer a threat,” he added, “and the facility has been evacuated.”