Thirty people were injured as severe turbulence tossed terrified passengers and crew around a Turkish Airlines plane cabin passing over the US on Saturday.

Dozens of ambulances lined up in front of a terminal at New York’s JFK airport to quickly treat the injured coming off the flight from Istanbul.

Steve Coleman, a spokesman for the Port Authority of New York and New Jersey, said 28 people were taken to Jamaica Hospital Medical Center in Queens and two went to Queens Hospital Medical Center. A flight attendant had a broken leg, Coleman said.

Turkish Airlines flight 1 hit the turbulence while passing over Maine about 40 minutes before landing. The crew declared an emergency while the Boeing 777 was still in the air, according to the Federal Aviation Administration.

“Nobody announced it or anything like that so we figured out something was wrong,” one passenger, Sead Nikaj, told ABC News. “Then I see people start flying on the plane. Then seeing blood all over. I had one of the ladies next to me, she really fell down from her seat on the floor and all her back was completely bloody, while someone that was working in the airplane, she cracked her leg I think completely.”

Another passenger, Amir Mehrbakhsh, said he saw one man frantically screaming. “I think he was like doing a religious chant. I kept hearing him say ‘Jesus’, like he was visibly distraught.”

He said of the turbulence: “There was like one or two seconds when it was subtle, but then it really started to pick up. Just because the drop was so sudden, a lot of people got lifted up and hit their head either on the ceiling or on the side of the plane, and so there were a lot of injuries pretty quickly.”

Turkish Airlines confirmed that the flight, carrying 326 passengers and 18 crew members, “encountered an unusual turbulence about 40 minutes before landing”. It said it was “deeply saddened by this unfortunate experience, and closely monitors the health status of injured passengers, and is making resources available to them.”

It was the second mishap on Saturday involving a plane in the New York metropolitan area. Earlier in the day, Newark Liberty international airport temporarily closed its runways after a flight from Montréal to Fort Lauderdale made an emergency landing with smoke in its cargo hold.