At least three people were killed, including the suspect, and seven others were injured in a shooting at a high school in St. Louis, in the US' Missouri.

A woman died at hospital, and a teen girl was pronounced dead inside the school, both of gunshot wounds, Xinhua news agency reported, citing a report by St. Louis Post-Dispatch.

The suspect, a male estimated to be in his 20s, was shot inside the school and pronounced dead at hospital.

The shooting was reported after 9 a.m. local time on Monday at Central Visual & Performing Arts High School. By 9:30 a.m., the entire area was blocked off by police, ambulances and a SWAT van. Students and staff streamed from the school with hands in the air.

The police did not indicate how the shooter got inside the building, the report said.