Two people were killed when a train carrying some 350 passengers and crew derailed early Sunday near Philadelphia, prompting officials to shut down service along a busy stretch of the northeast corridor.

Dozens of people were injured in the accident, which took place in the town of Chester, Pennsylvania shortly before 8:00 am (1200 GMT).

The accident occurred after "a vehicle was struck on the tracks," said Travis Thomas, fire commissioner for Chester, Pennsylvania, at a press briefing.

"There were two deceased, but they were not passengers on the train," Thomas said.

He declined to provide additional details about the accident or the victims.

However, news reports said the train, the Palmetto, en route from New York to Savannah, Georgia, struck a backhoe on the tracks and that the two fatalities were construction workers.

An Amtrak spokesman, Stephen Gardner, told reporters that officials from the National Transportation Safety Board were en route to the scene of the disaster to launch an investigation.

"The NTSB will provide all additional information about the crash," said Gardner, who added that workers would try to bring rail service back on line "as soon as possible."

Train service along a 30-mile (50-kilometer) stretch from Philadelphia south to Wilmington, Delaware was suspended, said Amtrak officials who did not give any indication as to when service would resume.

The accident caused the lead engine to derail on the train which was carrying 341 passengers and seven crew members.

"Initial reports are that some passengers are being treated for injuries," Amtrak said.

"Local emergency responders are on the scene and an investigation is ongoing," it added.

Thomas said later that 35 people received hospital treatment for "non-life-threatening" injuries.

"People are being re-routed back to Philadelphia to be reunited with their luggage," he added.

One passenger, 15-year old Wilson Holmes, was wrapping up a weekend visit with his mom and heading back to school in North Carolina, where he lives with his father, when the accident occurred.

"We were on the train and everything was going smoothly," he told reporters.

"We got off track and then there was a big explosion. Then there was a fire. The windows burst out. Some people were cut up... and then people started running," he said.

His mother, Monica Holmes, had dropped him off a half hour before the accident and sped back to the station when he called to tell her that there had been an accident.

"I dropped him off at 7:30 thinking he was on his way to his father," she said.

"He called and told me 'Mom, someone was killed on the train. It was a construction worker.' My heart just dropped," she said.

"I'm just thanking God that he's OK, and I pray for the other families that suffered the loss. I can't imagine it."