Southwest Airlines Flight 345 was arriving at LaGuardia from Nashville and reported possible front landing gear issues before landing on Runway 4 at 2:45 p.m. PT, FAA officials said.
LaGuardia Airport General Manager Thomas Bosco said the plane skidded down the runway on its nose and came to rest in a grassy area. One of the airplane's wheels popped off after the landing. No fires or fuel leaks were reported, only sparks. The nose of the plane could be seen on the ground.
"It was a normal landing. The plane rolled and the front dropped kind of fast," said Don Sheldon, a passenger on the plane. "Then it felt like it was swerving. A lot of smoke came out of the cabin. I think some people got bruised."
Richard Strauss, who was on a nearby plane waiting to take off for Washington, said the nose of the plane was "completely down on the ground. It's something that I've never seen before. It's bizarre."
Emergency slides were activated and all 143 passengers and six crew members were evacuated from the plane.
The Port Authority of New York and New Jersey said 10 passengers were treated at the scene; six of those people were transported to a hospital. Some passengers were complaining of back and neck pain. The flight crew was taken to a hospital for observation, and a police officer was treated for heat exhaustion, officials said.
LaGuardia Airport was closed for about an hour. One of the airport's two runways is closed, but officials hope to have it back open by Tuesday morning. Port Authority spokeswoman Lisa MacSpadden said "passengers need to be prepared for major delays."
LaGuardia is working with Southwest Airlines to move the jetliner from the grassy area and runway. Airport officials said they will check the runway for any damage once they get the OK from the National Transportation Safety Board.
The FAA and NTSB are investigating. Southwest Airlines released a statement saying it is cooperating with local authorities.
The incident came 16 days after Asiana Flight 214 crash-landed at San Francisco International Airport on July 6, killing two Chinese teenagers; a third was killed when a fire truck ran over her while responding to the crash, authorities said. Dozens of people were injured in that landing, which involved a Boeing 777 flying from South Korea.
ABC News and the Associated Press contributed to this report.