Police officers gather outside a United Parcel Service (UPS) facility after a shooting incident was reported in San Francisco, California, the United States, June 14, 2017. (Xinhua/Reuters photo)

SAN FRANCISCO, June 14 (Xinhua) -- Six people were shot Wednesday morning at a UPS facility in San Francisco and four were killed, including the shooter.

Acting Chief Toney Chaplin of San Francisco Police Department (SFPD) told a press briefing that officers rushing to the scene confronted with the shooter, who then turned an assault pistol to his head.

The UPS warehouse in San Francisco is on lock down on June 14, 2017 as police investigate a shooting incident. (Xinhua/Ma Dan)

The incident took place at about 9:00 a.m. local time at a sprawling UPS, or United Parcel Service, warehouse and customer service center in the Portero Hill neighborhood of the city on the U.S. West Coast.

While witnesses said the shooter was wearing UPS uniforms, and the package delivery company said earlier that those injured are its employees, Acting Chief Chaplin declined to identified those killed and injured.