Australian authorities Monday said they had called off their search for a boat carrying at least 55 asylum-seekers which disappeared suddenly off a remote Indian Ocean territory, adding they were unable to recover any bodies due to separate ongoing operations.
Officials suspended the search for a vessel off Christmas Island -- which was seen before it went down carrying men, women and children -- late on Sunday after failing to find any survivors.
Up to 13 bodies were spotted in the water during the extensive air and sea search. But customs said staff were occupied with a number of "high priority operations" in Australian waters and would not be able to recover the bodies on Monday.
"Our priority in those operations remains the protection of life, responding to other vessels which may require assistance and preventing further loss of life," a spokeswoman told Australian Associated Press.
"When those operations have been concluded and there is no further risk to life, Border Protection Command will endeavour to recover, where possible, any bodies."
The stricken vessel was initially spotted by a Customs plane off Christmas Island on Wednesday but when a boat attempted to intercept it the following day it had vanished.
Thirteen bodies and an upturned hull along with other debris were subsequently spotted during an extensive air and sea search which failed to find any survivors.
"The search has concluded," a spokeswoman for the Australian Maritime Safety Authority (AMSA), which had coordinated the search and rescue operation, told AFP on Monday.
The latest tragedy comes as the number of boat people attempting to reach Australia by boat has hit record levels with numbers expected to top 25,000 in the 12 months to June 30 despite punitive "no advantage" policies banishing refugees to remote Pacific detention camps.
There was no immediate information about the nationality of the passengers on the capsized boat, but Myanmar, Iraq, Afghanistan and Sri Lanka are common source countries for asylum-seekers arriving in Australia via people-smuggling boats, mostly from Indonesia.
Hundreds of refugees have died in asylum-seeker boat accidents in recent years, including a vessel which disappeared without a trace in the Sunda Strait in April with 72 on board. Last month 28 life jackets washed up on the Cocos Islands in the Indian Ocean, prompting fears of more drownings.
The latest tragedy has prompted calls for an investigation into the timing of the search, which came as other boats were arriving, including one carrying 78 people which sought help from authorities.
"If there's an issue of resource then that needs to be public," Ian Rintoul from the Refugees Action Coalition told the ABC.
Rintoul said until the government put policies in place to process asylum-seekers in Indonesia, people would continue to get on boats.
"If its policies are pushing people onto boats, then the least it can do, if it's not willing to escort boats ... is make sure that there are the resources available so we don't see the loss of life at sea," he said.