Particularly hard ice on Monday halted an Argentine ice-breaker and a rescued German vessel from proceeding with their arduous journey through Antarctic waters back to open sea, the Argentina news agency Telam reported.
Helicopters were flying overhead, looking for thinner, more navigable ice.
More than one week ago the Almirante Irizar helped free the Magdalena Oldendorff from eight-metre-ice.
Most of the crew aboard the Magdalena Oldendorff have been removed, but 18 are still on the ship that became stuck more than six weeks ago in the dead of the Antarctic winter.
The convoy has been slowed by bad weather and the Argentine navy has said it is difficult to estimate how long the journey through the nearly 1 000 kilometre-long ice field would take.
During winter in the Southern Hemisphere, the Antarctic continent is usually enveloped in ice until the end of September.
The German vessel, stuck in ice since June 11, had been carrying 79 Russian researchers from the Arctic and Antarctic Research Institute before South African Air Force helicopters picked up all but one of the Russians and 18 crew members. – Sapa-DPA