The Chinese icebreaker, the Snow Dragon, only managed to reach within six-and-a-half nautical miles (12 kilometers) of the trapped ship before encountering heavy ice it was unable to breach.

"Since the thick ice exceeds the ship's icebreaking capabilities and an upcoming cyclone will exacerbate icy conditions, we have to temporarily stall the ship," the captain of the vessel, Wang Jianzhong, told the Chinese Xinhua news agency.

The Snow Dragon was one of three icebreakers sent to free the MV Akademik Shokalskiy, which has become stranded about 100 nautical miles east of the French Antarctic station Dumont D'Urville.

Passengers are now hoping that Australia's Antarctic resupply ship Aurora Australis, which has the highest icebreaking rating of the three ships asked to help free the Akademik Shokalskiy, will manage to cut through the ice surrounding them. It is expected to arrive late on Sunday.

The third ship, the French icebreaker L'Astrolabe, is no longer involved in the rescue.

'Everybody safe and well'

The Australian Maritime Safety Authority (AMSA), which is coordinating the rescue, said the Chinese vessel would remain on standby, as it had helicopters on board that could take the passengers if all else failed.

The Akademik Shokalskiy is carrying 74 scientists and tourists on a privately funded expedition to follow in the footsteps of Australian explorer Douglas Mawson a hundred years ago. Most of the passengers are Australian. The Russian Foreign Ministry said there were 22 Russian crew members also on board.

The Russian embassy in Australia has said everyone on board is in good health and that there was "no threat to their lives or safety."

tj/jlw (AFP, Reuters)