MAKASSAR, Indonesia (Reuters) - A U.S. navy ship joined the search on Tuesday for an Indonesian airliner that went missing eight days ago with 102 people aboard, with the hunt focusing on a large metal object far down on the sea floor.
The object was discovered on Monday by Indonesian ships with sonar technology in water about 1,000 metres deep north of Mamuju in West Sulawesi province.
There was no immediate confirmation that it was the Adam Air Boeing 737-400 that vanished in bad weather on Jan. 1.
The USNS Mary Sears, an oceanographic survey ship, had reached the area being investigated, said First Air Marshal Eddy Suyanto, the Makassar air base commander heading the search.
"Mary Sears is currently working with Fatahillah (an Indonesian vessel), but as of yet there is no information on the result," Suyanto told a news conference.
The U.S. ship is equipped with side-scan sonar and satellite imagery capabilities, the U.S. embassy in Jakarta said.
The Indonesian navy was also sending at least four vessels to the scene, including one with a mini-submarine.
Indonesian navy chief Admiral Slamet Soebijanto told Radio Elshinta that local equipment so far had not been able to identify the object and the mini-submarine was only able to reach up to a depth of 1,000 metres.
Indonesian officials will be cautious in announcing any discovery after erroneously saying the plane had been spotted in the mountains of Sulawesi on Jan. 2 when accounts from local villagers were relayed unchecked to the highest authorities.
Besides Sulawesi's western coast, the search covers the Toraja highlands in the centre of the island and an area south of Manado, the North Sulawesi provincial capital where the plane was headed when it disappeared from radar screens.
Sulaeman, a rescue official, said a team had been sent to check reports from a villager that wreckage had been spotted in mountains a four-hour drive from Manado.
"We received a report saying the plane was found. The truth of it is blurry," he said by telephone.
First Air Marshal Suyanto denied the report.
"We have checked with the local air base and it's not true."
The plane vanished less than three days after a ferry with more than 600 aboard capsized and sank off Java.
Fourteen people were rescued on Sunday after drifting hundreds of miles on a life raft for nine days, bringing the total number of survivors to at least 248.
Many more were still unaccounted for and the Senopati Nusantara ferry had also yet to be found.
"I was told last night that my family had held a gathering to pray for my soul, believing I was dead," said Suriani, one of the survivors being treated at a state-run hospital in Makassar.
"I didn't think about death. Our main concern was whether we had enough food and water. So we often drank rain water and ate seaweed to save what we had," he said, his right arm still hooked up to an intravenous drip.
President Susilo Bambang Yudhoyono has called for an investigation into what went wrong in both cases as well as a general probe into the state of Indonesia's transport system.
Danang Parikesit of the Indonesian Transportation society, a private body, told foreign correspondents in Jakarta he was concerned about pressure on pilots to fly even in bad weather. "In the last two or three years, we have witnessed that the situation of transportation safety in indonesia is getting worse in all modes of transportation."
(With additional reporting by Mita Valina Liem, Muara Makarim and Johannes Mantiri in Jakarta)