SAN FRANCISCO — A gunman shot several coworkers at a sprawling UPS facility here Wednesday morning, then turned the gun on himself, UPS said.

NBC News reported that at least five people had been shot and four were dead, including the gunman. ‚ÄčNeither police nor UPS immediately confirmed the death toll. UPS spokesman Steve Gaut said the unnamed gunman was an employee who turned the gun on himself.

Police sealed off streets in city's Potrero Hill area after the shooting, which took place around 9 a.m. local time.

Following the shooting, what appeared to be two bodies lay in the middle of a street outside the facility, covered with yellow tarps, the San Francisco Chronicle reported.

#SFPD is at the scene of a shooting that occurred near 17th & Vermont. Please avoid the area, expect street closures and traffic delays #SF

— San Francisco Police (@SFPD) June 14, 2017

Zuckerberg San Francisco General Hospital, located about a mile from the facility, was put on alert immediately following the shooting. Spokesman Brent Andrew told the Chronicle that the hospital had accepted a few victims "and we’re expecting more.”

The large UPS processing facility is about two miles south of downtown. The four-story building, which covers an entire city block, is clearly visible along Highway 101 as drivers go into downtown San Francisco.

KPIX-TV reported the shooting happened during the daily 9 a.m. drivers' meeting. Auto shop owner Robert Kim told KPIX he heard five to eight rapid gunshots, then saw "a mob of UPS drivers” running down the street screaming “Shooter, shooter!”

A long column of two rows of UPS employees were escorted out of the building by armed police officers, KPIX reported. The employees had sheltered in place within the building.

The shooting took place in a different part of the building from the area where UPS customers pick up and drop off packages.

In a statement, UPS said local law enforcement had control of the facility and that the company was cooperating with the investigation.

These employees on the roof were rescued by police

— Kevin Wood (@megakwood) June 14, 2017

This is a developing story. Reload for the latest details.