Six of the casualties were taken to hospital after Southwest Airlines Flight 345 skidded off the runway, said airport general manager Tom Bosco.

Emergency vehicles surrounded the Boeing 737 from Nashville, which had 143 passengers and six crew on board.

The airport was shut temporarily, but later opened.

In an evening news conference, Mr Bosco said the plane's front wheel collapsed when it landed on runway four at 17:40 (21:40 GMT) on Monday.

He said the aircraft skidded on its nose before coming to rest in a grassy patch about half way down the runway. Emergency crews were seen spraying foam on the nose of the plane.

"We are assessing physical damage to the runway caused by the incident and we hope to have everything open by [Tuesday] morning," Mr Bosco said.

The Port Authority, which oversees the area airports, said the passengers had exited the plane by using emergency chutes.

Port Authority spokeswoman Lisa MacSpadden said those who were injured during the landing suffered back and neck injuries.

The crew was also taken to hospital for observation.

The Federal Aviation Administration and the National Transportation Safety Board are investigating the incident.

Passengers said it had been a rough touchdown.

"It was just a bang and a bounce and then just a slam on the brakes and then it was a skidding feeling," Kathy Boles told CNN.

"You could tell they were trying to stop the plane. It was very clear as soon as we went down that something was really wrong."

Four people reportedly suffered anxiety attacks, according to the Associated Press news agency.

Dallas-based Southwest Airlines said in a statement: "All customers have been deplaned and transferred to the terminal. Southwest is cooperating with local authorities."