HOUSTON - A shooting occurred at the US Army base of Fort Hood in Texas Wednesday afternoon, leaving at least one killed and several others injured, US media reported.

The incident is being treated as an active-shooter situation as the shooter is still at large, local TV KWTX, a Columbia Broadcasting System (CBS) affiliate, quoted a post spokesman as saying.

The spokesman also confirmed one person was killed, but didn't specify how many others were injured.

Multiple reports, quoting unnamed sources, said the shooter is hiding in a medical brigade building inside the military installation. Some media said at least three people were shot injured.

Fort Hood has ordered everyone at the Texas Army base to "shelter in place." The order was sent on the base's Twitter feed and posted on its Facebook page.

Some anonymous sources told the US media that warning sirens sounded at the military base and there appeared to be a standoff between the shooter and authorities.

Central Texas College in Killeen, which is 4 miles (6.4 km) from Fort Hood, was evacuated as a precaution. The school's website said all evening and night classes were canceled.