LONDON — In a dramatic operation displaying unusual international harmony in one of the world’s most remote and inhospitable places, a red-and-white Chinese helicopter on Thursday rescued 52 passengers trapped for more than a week aboard an icebound Russian research ship in Antarctica, ferrying them a dozen at a time to an Australian icebreaker.

The twin-rotor helicopter, based on a Chinese icebreaker, the Xue Long, or Snow Dragon, flew several sorties across miles of packed ice to pluck scientists, tourists and journalists from a landing zone next to the marooned vessel, the Akademik Shokalskiy.

The blue-hulled Russian ship was surrounded by such dense and extensive pack ice that it could not move, and vessels designed to break through ice could not get near. Images from the people being rescued showed them smiling as they walked single file across the ice to a landing area that had been cleared by passengers and crew members to enable the helicopter to touch down. Other images on the Internet showed crew members hauling sleds with luggage.

As the rescue got underway with the arrival of the Chinese helicopter, Chris Turney, a leader of the research expedition and a professor of climate change at the University of New South Wales in Australia, said in a message on Twitter that the Chinese helicopter had arrived. “It’s 100% we’re off!” he wrote. “A huge thanks to all.”