OTTAWA (AP) _ A former employee of Ottawa's transport agency shot dead four people at the city's main bus garage Tuesday, then killed himself with his high-powered rifle, police said.

The attacker opened fire with a .306-caliber rifle in mid-afternoon in a cavernous garage housing about 500 buses.

Authorities said they had spoken to the gunman's family, but did not immediately release his name or the names of the others killed.

Two other people were hospitalized with bullet wounds, police said.

``He was coming here to make some trouble. He lost it,'' said Sylvain Couture, a mechanic who witnessed the shooting.

A transport agency spokesman, Mike Sheflin, said there were about 100 workers in the immediate area of the shooting and there was a rush to get out when the announcement was made to evacuate.

``It's a great trauma,'' he said.

The area around the garage _ an industrial section in the Canadian capital's east end _ was sealed off by police.

Couture said he saw the man shoot two people inside the stockroom.

``One guy yelled over the PA, `There's a guy with a gun, call 911.'''

Garage attendant Marcel Gleason said there was a rush to get out of the building once the gun shots were heard.

``They told us to walk out and everybody was running out,'' he said. ``Everybody was scared. We heard the shots.''

The shutdown of the bus garage caused transit delays in parts of the city as scores of routes were affected.