LOS ANGELES, Dec 9: A young gunman opened fire inside a Christian youth mission centre outside Denver on Sunday, killing two staff members in their mid-20s and wounding another two, police said.

The incident came just days after a teenager armed with a semi-automatic rifle opened fire on Christmas shoppers at an Omaha shopping mall on Wednesday, killing at least eight people before turning the gun on himself.

Police in the Colorado town of Arvada said the missionary centre victims — a man and a woman both employed by the centre -- died in hospital after the gunman opened fire just after midnight.

Two other men aged 22 and 23 were receiving treatment for gunshot wounds, with one of them critically injured, a police statement said.

The suspect was described as a white male possibly 20 years of age. He fled the premises of the organisation Youth with a Mission on foot, according to the statement, which did not identify the victims.

Police said the gunman was wearing a dark jacket and a dark “beanie” skull cap. He may have had a beard and may have worn glasses, they said.

Youth with a Mission, which has offices worldwide, trains young American and international students to become missionaries in Europe, Africa and Asia.

Its Arvada premises employ 127 people, according to the group’s website.

“It is with great sadness that we report the shooting death of two staff members at our YWAM Denver (Arvada) training location,” the organization said.—AFP