(CNN) -- Thirteen people left adrift off the coast of Indonesia after their boat sank have been rescued by a passing coal freighter, the head of the local search and rescue agency said Tuesday.
The number of survivors found from the boat, which went down over the weekend, now stands at 49 -- a fraction of the 218 to 248 people estimated to have been on board.
Disaster management officials have said that most of those on board the ill-fated vessel, which was headed for Australia, were asylum-seekers from Middle Eastern countries, including Iran, Iraq and Afghanistan.
The 13 people rescued by the coal freighter had been floating out at sea for two days, holding on to debris or whatever they could find, said Sutrisno, the head of the East Java Search and Rescue Agency who like many Indonesians uses only one name.
The survivors, who were found Monday, are in good condition, he said.
Hopes for recovering any remaining passengers are fading, though. The rest of those who were on board the boat missing and feared dead, Sutopo Purwo Nugroho, spokesman of the National Disaster Management Agency, said Monday.
The boat's capacity was about 100 people, he said. It was a traditional wooden boat, about two stories high.
Rescue operations, both air and sea, are still going on Tuesday.
The boat was headed to the Australian territory of Christmas Island when it went down, said Dody Sapiawin, a duty officer at Indonesia's National Search and Rescue Agency.
The Australian authorities were assisting in the search and have sent aircraft and a patrol boat to help.
Christmas Island is an Australian territory in the Indian Ocean, nearer to the Philippines than to Australia. The island is about 1,600 miles northwest of the western Australian city of Perth and 220 miles south of the Indonesian capital, Jakarta.
The Australian government has come under fire in the past for what some perceive as a soft border protection policy that encourages asylum-seekers to flee to Australia.
In December 2010, a boat carrying as many as 90 asylum-seekers crashed into the cliffs along Christmas Island, killing at least 48 people.
CNN's Kathy Quiano and Aliza Kassim contributed to this report.