The US today sent its heavy ice-cutter to rescue over 120 crew on board the Russian and Chinese ships trapped in the Antarctic, with ice up to four metres thick surrounding them.

The US Coast Guard announced yesterday that it would send the Polar Star after the Australian Maritime Safety Authority requested it to assist the Russian-flagged Akademik Shokalskiy and Chinese-flagged Xue Long that remain ice-bound in the Antarctic.

Russia and China have also requested assistance from the US.