A boat carrying 150 people believed to be asylum seekers capsized in the Indian Ocean on Tuesday, killing four people, Australian officials said.

The boat turned over in rough seas north of Christmas Island, an Australian territory 310 miles south of Jakarta, Indonesia, Australia's Customs and Border Protection said in a statement.

Two navy ships had earlier been sent to assist the vessel but were unable to board it due to bad weather. The ships were escorting it to Christmas Island, where Australia operates a detention camp for asylum seekers, when it flipped.

Rescuers dropped life rafts into the water and plucked 144 survivors to safety. Four bodies were recovered and the search was called off Tuesday night, the border protection authority said.

Christmas Island is a popular destination for asylum seekers who crowd into rickety boats at Indonesian ports and pay people smugglers to ferry them to Australian shores. Hundreds have died while attempting the journey in recent years.

Last week, another boat carrying asylum seekers sank off Christmas Island. Officials recovered the body of a baby boy and were unable to find 8 passengers who vanished in the water.