Ottawa police say two men who were seriously injured in a single-vehicle rollover on Baseline Road Saturday have died.

The two victims were sent to hospital in "critical, unstable condition" after paramedics responded to the crash around 2:30 p.m. just west of Fisher Avenue.

Paramedics said they both suffered "multi-system trauma" in the crash.

Ottawa police say the two men in their early 20s died Saturday and that their identities are not being released at this time.

Police told CBC News the car was heading east on Baseline Road when it hopped the median, crashed into the Experimental Farm field and rolled.

"[The car] went into the Experimental Farm, hit one of the posts holding up the fence, flipped in the air twice and then rolled an additional three or four times," said Michael Whelan, who lives on that section of Baseline Road and saw the collision from his front window.

"One of the [people], I'm not sure whether it was the driver or the passenger, was ejected from the vehicle. I dialled 911 right away."

Investigators are still working to determine the cause of the crash and say speed is a possible factor. It was not raining at the time, police added.

Police closed a section of Baseline Road for approximately five hours before it was reopened to motorists.

Traffic officers were out watching for speeding drivers on the same stretch of road on Sunday.