A deadly shooting took place Wednesday morning in an industrial section of San Francisco that by all accounts appears to have been committed by a UPS employee against his fellow employees. The shooter took his own life, and at least one news source has identified him.

The area of San Bruno Avenue and 17th Street on Potrero Hill was temporarily on lockdown as of about 9 a.m. due to an active shooter situation reported inside the UPS headquarters there. NBC Bay Area reported that multiple ambulances were on the scene and that at least five people were shot, and possibly more.

The Associated Press later confirmed that SF General had received "multiple" victims but has not gotten a definitive number. CBS 5 reports that three were wounded.

KRON 4 reported that there were multiple deaths, and first reported that the shooter was among the dead. ABC 7 says that the gunman died as did three other people, and that the gunman shot himself upon being confronted by police.

The Chronicle has it via a UPS spokesperson that "at least four employees were involved in the incident." In a further update, the Chronicle reports that three people were shot and killed, and that the gunman died as well.

Though it was initially unclear where the shooting began, it quickly became clear that it was inside the UPS sorting center and warehouse on San Bruno Avenue. Mission Local and ABC 7 were among the first to report the location, and via a UPS employee who escaped unharmed, ABC 7 learned that the shooting occurred during a morning meeting among drivers.

Heavy police activity began in the area just after 9 a.m., and as of 10 a.m., ABC 7 says that police have the building under control.

A media staging area originally planned at 17th and Potrero Avenue has been moved to Mariposa and Utah.

A photo of the UPS warehouse from the corner of 17th and San Bruno:

ABC 7 further shows us the activity around the UPS building, and some tweets suggest that some UPS employees had escaped to a roof and were calling for help. One witness in the area suggests that the shooting suspect is a UPS driver who targeted another employee.

We'll update you as we learn more.

Update: UPS has issued a statement saying "UPS confirms there was an incident involving employees within the company’s facility in San Francisco earlier this morning. Local law enforcement have control of the facility and are conducting an investigation. The company is cooperating with law enforcement. We cannot provide information as to the identity of persons involved at this time, pending the police investigation.”

Update 11:25 a.m.: Police continue to comb the UPS facility for more victims and witnesses, and possible accomplices. The shelter-in-place order remains in effect for the immediate area from 15th to 18th Street, between Potrero Avenue and Vermont Street.

Update 11:45 a.m.: CBS News reporter John Goodwin puts the number of dead at three, saying six victims were shot and the shooter then turned gun on himself. It's unclear whether the shooter is being counted among the three deceased.

Mayor Ed Lee issued the following statement: "“At this point, the San Francisco Police Department is still investigating the events that occurred this morning. I want to thank our brave officers of the San Francisco Police Department, and our dedicated employees at 911 and San Francisco General Hospital.

I also want to offer my condolences and thoughts for the individuals and families affected by the senseless act of violence at the UPS facility. We all know the familiar faces of our local UPS drivers and delivery persons. Today’s tragedy will be felt in every community served by these committed employees.

We are always saddened when someone loses a life to gun violence. Even one shooting and one victim is too many.”

Update 2:20 p.m.: The shooter has been preliminary identified as Jimmy Lam, a resident of the Sunset district and a father of children.

* This post has been updated throughout.