Santorini, Greece ? Scores of passengers climbed down rope ladders to rescue vessels after a Greek cruise ship struck a reef Thursday and started listing in the Mediterranean, forcing the evacuation of 1,600 people including North Carolina high school students.

Authorities said most of the nearly 1,200 passengers on the Greek-flagged Sea Diamond were American tourists. At least two school groups from Canada, more than 100 Spaniards and a crew of almost 400 were also on board when the ship hit the rocks off the island of Santorini shortly before 4 p.m.

Passengers said most people remained calm, though there were some tense moments waiting for the rescue.

“People were nervous, women were screaming and it was a struggle to get to a life jacket,” said passenger Ben Kucenko, a telecoms technician from Jeelong, Australia. “We were scared the boat was going to tip over. We could barely walk.”

Tiffany Gittens, an event coordinator from New York, said at first passengers mistook the sound of rocks screeching against the boat for an anchor dropping.

“We were all sitting in the dining room, and the boat started to tilt and it started to tilt more to the other side,” Gittens told the Associated Press, speaking by telephone from Santorini after her rescue.

More than a dozen ships were involved in the rescue effort, along with six navy rescue helicopters, two military transport planes and four warships.

“The ship was evacuated quickly and successfully. … No one had as much as a nose bleed,” Merchant Marine Minister Manolis Kefaloyiannis said.

“With a ship this size, it’s like dealing with a 12-story building. It’s a difficult operation,” he said.

The Merchant Marine Ministry said 1,195 passengers and 391 crew members were on board.