At least 54 people have been rescued from the ocean more than a day after an asylum-seeker boat heading for Australia disappeared off the Indonesian coast with more than 150 people aboard.
After Indonesia abandoned its search, six people were rescued overnight by a cargo ship and 48 more were pulled from the water by an Australian navy crew after being located by spotter planes late on Thursday.
"Three have serious injuries but are in a stable condition," the Australian Maritime Safety Authority (AMSA) said, adding that the search was being scaled back.
"Vessels will remain on scene overnight, but have limited search capability until daylight Friday."
Jason Clare, Australian home affairs minister, said there were serious concerns for those still missing, who include women and children.
"We have grave fears for a lot more," he said. "Don't underestimate how hard it is to find people in the middle of the sea."
Search is under way by Australian and Indonesian rescue workers for the missing boat, believed to be carrying scores of asylum seekers.
The head of Indonesia's rescue mission at Merak port in western Java said it appeared that one of the survivors had been bitten by a shark.
AMSA said the survivors were expected to be taken to Merak in Indonesia's Java for medical attention. An Indonesian rescue boat carrying doctors was steaming to the area where the boat sank along with a police ship.
Four merchant vessels were continuing the search alongside Australian Royal Navy's HMAS Maitland and two P3 Orion aircraft.
A distress call on Wednesday said the boat had engine trouble, according to the AMSA.
"We have grave fears for a lot more," he said. ''Don't underestimate how difficult this task is; don't underestimate how big the sea that we're searching is.''
- Jason Clare, Home Affairs Minister, Australia
This is the latest in a series created by a growing human-smuggling trade in which thousands of would-be refugees from countries including Afghanistan, Iran and Sri Lanka travel from Indonesia to Australia in overcrowded fishing boats.
The crew of a merchant ship taking part in the search, Liberian-flagged APL Bahrain, spotted survivors in the water early on Thursday 75km southwest of Java and rescued six people.
The Bahrain's captain, Manuel Nistorescu, told the Fairfax Media website that he also saw what he believed were bodies in the water.
"I think I saw some of them dead," he said.
Nistorescu said the six rescued, all Afghan men, had been in the water for almost 24 hours.
There were also women and children aboard the asylum-seeker boat when it sank, said Nistorescu.
Richard Marles, Australia's junior foreign minister, said the emergency highlighted the need for Australia to urgently establish detention camps in the Pacific island states of Papua New Guinea and Nauru to hold asylum seekers who reach Australia by boat.
The government hopes to send the first asylum seekers to a tent camp on Nauru in September in a strategy to deter others from attempting the same boat journey.
Asylum seekers often target Christmas Island, off Australia's northwest coast, to get to the country. They make the journey from Indonesia in boats that are usually overloaded and poorly maintained.
In August, 60 asylum seekers were reported missing off the Australian coast.
In June, a boat with 200 asylum seekers sank near the island - 17 bodies were found and another 70 were feared dead after a three-day search.
That was the second boat to sink in a week, reigniting the debate on asylum in parliament.