CANBERRA, Australia — An Australian icebreaker carrying 52 passengers who were retrieved from an icebound ship in the Antarctic resumed its journey home on Saturday after it was halted for a second potential rescue operation.

The Aurora Australis had been slowly cracking through thick ice toward open water after a Chinese ship's helicopter on Thursday plucked the passengers from their stranded Russian research ship and carried them to an ice floe near the Australian ship. But on Friday afternoon, the crew of the Chinese icebreaker that had provided the helicopter said they were worried about their own ship's ability to move through the ice.

The Australian Maritime Safety Authority's Rescue Coordination Centre, which oversaw the rescue, told the Aurora on Friday afternoon to stay in the area in case help was needed.

Under international conventions observed by most countries, ships' crews are obliged to take part in such rescues and the owners carry the costs.

AMSA said the Aurora was allowed on Saturday to continue its journey despite the Chinese ship Snow Dragon, or Xue Long in Chinese, remaining stuck in ice.

"The master of Xue Long has confirmed to AMSA that the ship is safe, it is not in distress and does not require assistance at this time," AMSA said in a statement.

An attempt by the Snow Dragon to manoeuver through the pack ice during optimal tidal conditions early Saturday failed. The Chinese ship remains stuck several kilometers (miles) from the Russian icebreaker Akademik Shokalskiy, from which the passengers were rescued. The Russian ship has been immobile since Christmas Eve.

A reporter for China's official Xinhua News Agency aboard the Snow Dragon, Zhang Jiansong, reported an iceberg appeared overnight and blocked the ship's return route. He said the ship will again try to find a way out, possibly as early as Monday.

Chinese President Xi Jinping praised the crew for their rescue work and asked that all efforts be made to ensure the Snow Dragon would safely navigate out of the icy region.

AMSA said the Aurora resumed its journey to Australia's Antarctic base, Casey Station, on a resupply mission before returning to the Australian island state of Tasmania in mid-January with the rescued scientists, journalists and tourists.

Andrew Peacock, an Australian doctor and photographer who was rescued from the Russian ship, spoke Friday of his fellow passengers' frustration aboard the Aurora over the latest delay in their journey home. He said they were quiet and appeared tired as they took stock of their situation.

"So our time down south is not over yet and we are going to be delayed in our return to friends and family by some time yet, which is frustrating," Peacock said in an email before the Aurora was given permission to continue.

There had been "some apprehension" on Thursday before the first dozen passengers boarded the Chinese helicopter for the flight from the stricken Russian ship, he said.

"There was palpable relief on faces as each group of people arrived into the mess area of the Aurora Australis to meet those who had arrived on earlier flights," Peacock said.

Adding to the passengers' fatigue, they had to adjust to a five-hour time difference. The Russian ship had operated on New Zealand time (+13:00 GMT) in the endless sunshine of the Antarctic summer, while the Aurora worked on Australian Western Standard Time (+8:00 GMT).

The Aurora had offloaded only 70 percent of its cargo at Casey last month before it was diverted to the rescue.

It will now deliver the remaining 30 percent, which includes scientific equipment vital to research projects scheduled to be carried out during the narrow window of the Antarctic summer.

Australian Antarctic Division acting director Jason Mundy said the rescue had stretched resources for the summer research program, which he hoped to recoup from the Russian ship's insurer.

In addition to the disruption to Australia's scientific program, the rescue would cost Australian taxpayers 400,000 Australian dollars ($358,000), Environment Minister Greg Hunt's spokesman John O'Doherty said.

"This incident is a reminder that everyone operating in the Southern Ocean ... has to put safety ahead of everything else," Hunt said in a statement.

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Associated Press writer Kristen Gelineau in Sydney and Didi Tang in Beijing contributed to this report.