Rescuers battled high waves on Sunday as they searched for 200 asylum seekers still missing after their wooden ship sank off Indonesia's main island of Java. So far only 33 people have been plucked alive from the choppy waters.

Two were children, aged 8 and 10, found clinging to the broken debris of the boat five hours after the accident.

"It's really a miracle they made it," said Kelik Enggar Purwanto, a member of the search and rescue team.

Survivors told authorities they were fleeing economic and political hardship in Afghanistan, Iraq, Iran and Turkey, said Lt. Alwi Mudzakir, who was heading the operations.

They were heading to Australia in search of a better life.

Mudzakir, a maritime police officer, blamed on Saturday's accident on overloading, saying the vessel - packed with 250 men, women and children - appeared to have been carrying more than twice its capacity.

When the boat became unsteady 20 miles (32 kilometers) off Java's southern coast, people started panicking, causing it two sway violently back and forth, until finally, it capsized.

Indonesia, a sprawling archipelagic nation of 240 million people, has more than 18,000 islands and thousands of miles (kilometers) of unpatrolled coastline, making it a key transit point for smuggling migrants.

Those on the ship that sank on Saturday had passed through the capital, Jakarta, three days earlier without any legal immigration documents, according to police.

An unidentified group loaded them onto four buses and brought them to a port, promising to get them to Christmas Island, an Australian territory in the Indian Ocean.

Local television showed a half-dozen survivors at a shelter in Trenggalek, the town closest to the scene of the sinking, some with dazed, empty expressions as they sat on the floor drinking and eating. Several others were taken to a nearby hospital in critical condition.

One of the men, Esmat Adine, earlier told the official news agency Antara that when the ship started to rock, triggering the panic, people were so tightly packed they had nowhere to go.

"That made the boat even more unstable, and eventually it sank," said the 24-year-old Afghan migrant, adding 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.

At Prigi, the nearest port, several members of the national search and rescue team were getting ready to head out to sea, local television footage showed.

Empty body bags could be seen on board.

Mudzakir said so far 33 people have been rescued. Many of them, according to Purwanto, the search and rescue official, were suffering from severe dehydration and exhaustion.

But they and others were giving up hope of finding more survivors, saying weather was bad and four fishing boats, two helicopters and a navy war ship already involved in the operation were battling 4-meter- (13-foot-) high waves.

"They have scoured a 50-mile radius but haven't found anything," Mudzakir said.

Given the strong current, high waves and extreme weather, there was little chance anyone would be able to survive more than 24 hours at sea, he added.

It's not uncommon for asylum seekers, many of whom travel in overcrowded, rickety boats, to die before they make it to Australia.

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.