A gunman shot four staff members at a missionary training centre near Denver early Sunday, killing two, after being told he couldn't spend the night.

A police officer directs worshippers from a parking lot near a youth ministry dormitory on the Faith Bible Church campus in Arvada, Colo.
(David Zalubowski/Associated Press)

About 12 hours later and 105 kilometres away in Colorado Springs, a gunman fatally shot a parishioner at a megachurch and wounded four other people before a guard killed him, police said.

One of the hospitalized victims from the second attack died Sunday at about 10:10 p.m. local time, said Amy Sufak, a spokeswoman for Penrose Community Hospital in Colorado Springs.

The police chief in Arvada, a suburb about 25 kilometres west of Denver where the mission workers were shot, said the shootings may be related to those in Colorado Springs but declined to elaborate. No one had been captured in the Arvada shootings, authorities said.

Colorado Governor Bill Ritter has ordered state authorities to assist in the investigation.

Police have identified the dead in the Arvada shooting as 26-year-old Tiffany Johnson of Minnesota and 23-year-old Philip Crouse of Alaska.

New Life Church was founded by the Rev. Ted Haggard, who was fired last year after a former male prostitute alleged he had a three-year, cash-for-sex relationship with him.

The church is one of Colorado's largest with about 10,000 members