Large metal objects that may be the wreckage of a missing Indonesian jet have been located on the seabed, an Indonesian navy commander says.
Prayers have been held for the missing passengers
First Admiral Gatot Subyanto said the metal had been detected in three locations by Indonesian naval ships off the west coast of Sulawesi.
He said it was not clear what the metal was but a US navy ship is due to arrive which may be able to identify it.
The Boeing 737 disappeared from radars a week ago carrying 102 people.
Meanwhile, there has been some good news in the hunt for survivors of a ferry disaster off the Javan coast nine days ago.
Fourteen people have been rescued by a passing ship.
This brings to around 250 survivors picked up so far - less than half the number of passengers believed to have been on board at the time it sank.
First Admiral Subyanto said naval ships combing the seas off Mamuju on Sulawesi's western coast for the missing jet had detected the metal objects between three and six kilometres apart on the seabed.
The search involves thousands of soldiers, police and civilians
"There were large metal objects at three different points, "he told the AFP news agency.
"The thing is, what these metal objects are, we cannot say. We do not have the necessary equipment."
The naval ships are equipped with a basic sonar system, but more sophisticated mapping equipment is needed to determine the objects' exact shape.
A US Navy ship, the USNS Mary Sears, carrying the necessary equipment, is expected to arrive in the area on Tuesday.
"We will direct them to the site," Admiral Subyanto told El Shinta radio.
Indonesia's navy had begun a search of the area on the advice of a local fisherman, who had seen a low flying plane, an officer involved in the operation said.
A massive air, land and sea operation has been under way to look for the Adam Air flight that went down on its way from Java to the northern Sulawesi town of Manado on New Year's Day.
A team of US investigators has already arrived to help with the search, together with nearly 3,000 soldiers, police and civilians.
First Air Marshal Eddy Suyanto told the French news agency AFP earlier that Monday's search would continue to focus on areas "that have already been combed".
"There is no extension of the search, but it is now more detailed," he said.
Bad weather has hampered the search, as have false leads.
Government officials had to apologise soon after the plane's disappearance for erroneously saying that the wreckage had been found.
Vice-President Yusuf Kalla said over the weekend that the search would continue despite the cost.
"It's impossible that it just disappeared," he said. "Even if it takes a month ... we have to keep searching."
But some relatives of missing passengers have admitted to reporters that they believe the chances of anyone being found alive are slim.