A bus carrying 26 students and several staff from Bedford Park School in Toronto was rear-ended by a public transit bus in New York's Lincoln Tunnel Wednesday.

No one on the school bus was injured, according to Toronto District School Board spokesman Ryan Bird.

"Speaking with staff on the bus, they said they felt a bump from behind around 9:40 this morning," Bird said in a statement. "All students and staff are safe, no injuries reported."

He said damage to the bus, which has since left the tunnel, is relatively minor and that the students would continue on their graduation trip.

"A little excitement this morning," tweeted Kevin Battaglia, the principal at the school, who was on the bus. "[Our] bus was rear-ended by another bus in the Lincoln tunnel....we are all fine."

Battaglia later apologized for the tweet.

"My apologies for referring to the accident this morning as excitement...we had no idea there was any serious damage behind us," he tweeted.

My apologies for referring to the accident this morning as excitement...we had no idea there was any serious damage behind us. —@kevinbattaglia1

The crash happened in the centre tube on the New York side of the tunnel connecting it with New Jersey, said Joe Pentangelo, spokesman for the Port Authority of New York and New Jersey police, which operates the tunnel.

He said 35 to 40 people on the transit bus were hurt. The four most seriously injured suffered neck and back injuries. The Fire Department of New York said none of the injuries are considered life-threatening.

Initially, there was apparent jurisdictional confusion on how to respond to the accident, as one side of the tunnel is in New Jersey and the other side of the tunnel opens in New York.

Passengers could be seen walking out of the tunnel and being carried out on stretchers as fire department crews were on the scene with emergency equipment.

The crash closed the centre lane and caused mass transit delays in New York.