Indonesian volunteers worked late into Monday to rescue six sperm whales using ropes and patrol boats and haul them back into the sea off Aceh province.

Four other whales died because of injuries and exhaustion, a fisheries official said on Tuesday.

Nur Mahdi, the head of Aceh's marine and fisheries office, said two of the whales who were badly bruised, died early Tuesday. The other two, which looked extremely weak, died a few hours later.

The whales beached at Ujong Kareung beach in Aceh province on Monday, attracting hundreds of onlookers who posed for selfies with the stranded mammals.

Rescue effort

It wasn't immediately known why the sperm whales had washed up in shallow water.

Mahdi said whale pods follow a group leader and can end up beaching if the leader swims too close to shore due to sickness or other reasons.

Dozens of volunteers waded on to the reef to rescue the stranded sperm whales, which are among the biggest mammals on earth, growing up to 12 meters and weighing up to 57 metric tons.

"Some people got injured on the coral and the high tide was also an obstacle but we tried our best," said Sapto Aji Prabowo, head of the Aceh conservation agency.

"It is an important lesson for us on how to evacuate such huge animals if it happens again."

ap/rc (AP/Reuters)