Indonesia's search and rescue chief said today he was "confident" two large objects detected under the Java Sea were the wreckage of AirAsia Flight 8501.
One of the sea bed objects was 9.4 by 4.8 metres (31x15ft) and half a metre (20ins) high, National Search and Rescue Agency chief Henry Bambang Soelistyo said.
The second, found nearby, was 7.2 metres (24ft) by half a metre.
"I'm confident this is part of the AirAsia plane," Mr Soelistyo said. A remote-controlled vehicle has been sent to the area.
Mr Soelistyo said Indonesian navy warship the Bung Tomo detected the objects using sonar yesterday. By midnight local time, searchers had zoomed in with a Geological Survey Ship to take dimensions.
Teams are now trying to capture images of the objects.
The Airbus A320 carrying 162 passengers and crew went down on Sunday, half-way into a flight from Surabaya, Indonesia's second-largest city, to Singapore.
Minutes before losing contact, the pilot told air traffic control he was approaching threatening clouds, but was denied permission to climb to a higher altitude because of heavy air traffic.
It remains unclear what caused the plane to plunge into the sea. The accident was AirAsia's first since it began operations in 2001, quickly becoming one of the region's most popular low-cost carriers.
Meanwhile Indonesian authorities grounded AirAsia flights from Surabaya to Singapore, saying the plane which crashed into the Java Sea should not have flown on the day of the tragedy.
The country's Transport Ministry said the budget airline did not have a permit to fly on Sundays. AirAsia said it was reviewing the suspension.
After nearly a week of searching for the victims, rescue teams battling monsoon rains pulled many more bodies from the sea, some still strapped to their seats.
Of the 30 recovered so far, 21 bodies were found yesterday, many of them by a US Navy ship.
The vessels included eight sophisticated navy ships from Singapore, Malaysia and the US, equipped with sonars for scouring the sea bed to pinpoint wreckage and the all-important black boxes.
"Many passengers are believed to be still trapped inside the plane's fuselage and could be discovered soon," said search and rescue agency director of operations Suryadi Supriyadi. "God willing, we would complete this operation next week."
The data recorder contains crucial information like engine temperature and vertical and horizontal speed. The voice recorder saves conversations between pilots and other sounds coming from inside the cockpit.
Toos Saniotoso, an Indonesian air safety investigator, said investigators "are looking at every aspect" as they try to determine why the plane crashed. "From the operational side, the human factor, the technical side, the ATC (air traffic control) - everything is valuable to us," he said.
Bad weather, which has hindered the search for the past several days, remained a worry. Rain, strong winds and high waves were forecast until tomorrow. Strong sea currents have also kept debris moving.
Colonel Yayan Sofiyan, commander of the Bung Tomo, said his vessel pulled seven bodies from the choppy waters, five still fastened in their seats.
A total of 30 bodies have been recovered, more than a third by a US Navy ship, the USS Sampson.
Generally, aviation experts say the more passengers, luggage and parts of the aircraft that remain intact indicate the plane hit the water in one piece.
That would signal problems like a mechanical error or a stall instead of a mid-air break-up due to an explosion or sudden depressurisation.
Four crash victims have been identified and returned to their families, including a flight attendant and an 11-year-old boy.
After Friday prayers, the holiest day of the week for Muslims, more than 200 people gathered at a mosque in Surabaya to remember the victims.
"We pray that the passengers in this AirAsia tragedy will be received by Allah," the imam said, "and that all their sins will be forgiven by Allah."
For family members, the seven-day wait has been agonising with local media covering every development and theory, many of which have proved to be untrue - including a false report that a body was found wearing a life jacket, which would have indicated passengers had time to prepare for the impact or were able to put them on after hitting the water.
As more corpses started to arrive in Surabaya, some relatives said they were simply worn out. But they were encouraged by the reports that parts of the plane had been found and hoped that everyone on board would be retrieved.
"Let's hope the news is true," said Ongko Gunawan, whose sister was travelling with her husband and their child. "We need to move on."