Scores of people are feared dead after a wooden ship carrying about 250 asylum seekers sank off Indonesia's main island of Java.
So far, only 33 people have been rescued, and fishing boats are searching for the more than 200 missing passengers.
Bad weather and 13ft waves are hampering the rescue operation, said Lieutenant Alwi Mudzakir, a maritime police official heading the search. "We fear that a large number of victims will not be rescued," he said.
Police blamed the accident on overloading, telling Indonesia's official Antara news agency that the vessel appeared to have been carrying more than twice its capacity.
Lt Mudzakir said some of those who were rescued told authorities that they were determined to seek asylum in Australia.
He said about 250 asylum seekers - mostly from Afghanistan, but also from Iraq, Iran and Turkey - were taken by four buses from Indonesia's capital, Jakarta, on Thursday by an unidentified group. The group promised to get the asylum seekers to Christmas Island, an Australian territory in the Indian Ocean, without legal immigration documents.
One of the survivors, Esmat Adine, told Antara that the ship started rocking from side to side, triggering widespread panic.
Because people were so tightly packed, they had nowhere to go, said the 24-year-old Afghan migrant. "That made the boat even more unstable, and eventually it sank," he said.
He added that he and others survived by clinging to parts of the broken vessel until they were picked up by local fishermen. He estimated that more than 40 children were on the ship. Lt Mudzakir said that two children and a woman were among the 33 rescued.
Indonesia, a sprawling archipelagic nation of 240 million people, has more than 18,000 islands and thousands of miles of unpatrolled coastline, making it a key transit point for smuggling migrants. Last month, a ship carrying about 70 asylum seekers from Afghanistan, Iran and Pakistan capsized off the southern coast of Central Java province, and at least eight people died.