Updated

One contractor died and two Metro employees were injured in a welding accident in a Red Line subway tunnel between Union Station and the Judiciary Square stop early Sunday, Metro said.

Metro Spokeswoman Caroline Lukas told The Associated Press by telephone that the contractor, who was providing welding services, died at a hospital where he was taken after the accident. The two others were in serious condition in local hospitals with non-life threatening injuries, according to Lukas.

No identities were immediately provided following the accident, which occurred shortly after midnight and involved no passengers.

The Washington Post said the accident involved an explosion and fire that broke out in a tunnel were some of the major rebuilding work was ongoing as part of a $5 billion capital campaign.  Asked about the report, Lukas said there was no major fire and flames were quickly put out with hand-held fire extinguishers.

The Post said Red Line rail service had already been suspended late Friday -- prior to the accident -- as work had targeted an area along the line comprised of five key stations: Farragut North, Metro Center, Gallery Place, Judiciary Square and Union Station. Plans had called for the five stations to remain closed for the work until the resumption of normal service Monday morning, the paper added.

"The Red Line will continue to be shut down and free shuttle bus service provided as it was Saturday," Lukas told AP. The free shuttle buses are operating between Dupont Circle and No-Ma-Gallaudet stations.

She added that normal rail service would resume before the Monday morning commute.

A statement released by Metro said it was conducting an investigation into the cause of the accident and that the National Transportation Safety Board and others had been notified.

"All Red Line track work was suspended, and a Red Line safety `stand down' was ordered to brief crews on the incident, offer counseling services to anyone who needs them, and reinstruct employees on safety procedures," the state said. "Work will continue to restore the track after all safety briefings and on-site investigations have been completed."