A boat carrying dozens of asylum seekers has sunk off the coast of Indonesia, killing at least 21 people.

Search and rescue agency officials say 25 people were rescued Friday, Sept 27, and taken to Cikole village in the West Java district of Cianjur. They say the search is continuing for more survivors, but it's unclear how many people were aboard the boat and what countries they were from.

The boat was believed headed for Australia. The incident comes ahead of a visit by Australian Prime Minister Tony Abbott to Indonesia next week, his first since taking office. Australia's policy of turning back asylum seekers' boats has been sharply criticized in Indonesia.

Indonesia's vast islands and its proximity to Australia make it a popular exit point for the perilous journey.

In March 2013, a boat carrying 95 asylum seekers capsized off Australian coast. Hundreds have died making the treacherous journey over the past few years. Also in March, a naval vessel plucked 77 asylum-seekers to safety after their boat broke up on the way to Australia.