SYDNEY – A Russian research vessel and Chinese icebreaker stranded in Antarctica have broken free from the heavy ice that gripped them and are making steady progress towards open waters, the Australian Maritime Safety Authority (AMSA) said on Wednesday.

The Chinese icebreaker became trapped in isolated Commonwealth Bay last week after using one of its helicopters to ferry to safety the passengers of the stranded Russian vessel.

Australian rescue authorities advised the two captains to take advantage of cracks in the ice that appeared around the vessels on Tuesday evening. They have since made slow progress through lighter ice conditions towards the open sea.

"The Xue Long has advised RCC Australia it does not require any further assistance at this time," AMSA said in a statement. "The Akademik Shokalskiy continues to move through the ice field and RCC Australia is awaiting confirmation that it does not require any further assistance."

The Russian-owned research ship, Akademik Shokalskiy, left New Zealand on Nov. 28 to commemorate the 100th anniversary of an Antarctic journey led by Australian explorer Douglas Mawson.

It became trapped on Dec. 24, 100 nautical miles east of French Antarctic station Dumont d'Urville and about 1,500 nautical miles south of Tasmania.

While stranded, passengers amused themselves with movies, classes in knot tying, languages, yoga and photography, and rang in the New Year with dinner, drinks and a song about their adventure.

The United States Coast Guard ice breaker Polar Star, which was dispatched earlier this week to assist with the rescue operation, will continue to head towards the area until it is clear that both vessels are free of the ice field and no longer in danger, AMSA said.