SYDNEY, April 11 (Xinhua) -- Australian Prime Minister Tony Abbott said Friday that he was confident signals detected in the Indian Ocean in the past week were from the black box of missing Malaysia Airlines flight MH370.
"We have very much narrowed down the search area and we are very confident that the signals that we are detecting are from the black box," Abbott told reporters in Shanghai, China.
"Nevertheless, we're getting into the stage where the signal from what we are very confident is the black box is starting to fade," he said. "We are hoping to get as much information as we can before the signal finally expires."
Australian navy ship Ocean Shield has detected signals four times in the past week in a designated search zone in the Indian Ocean.
Addressing a luncheon event in the Chinese commercial center, Abbott said searchers knew the approximate position of the black box.
"We are confident that we know the position of the black box flight recorder to within some kilometers," he said.
Meanwhile, the Australian prime minister cautioned that confidence in the approximate position was "not the same as recovering wreckage from almost 4.5 km beneath the sea and finally determining all that happened on that flight."
Offering sympathy to the bereaved families of the 154 Chinese victims, Abbott said "Australia will not rest until we have done everything we can."
Noting that China was the first country to dispatch vessels once the search moved to the Indian Ocean, Abbott thanked the Chinese government and people for the help they had offered as Australia leads the search and recovery effort.
"China was the very first country to provide ships for the search, and we've been very grateful for the help," he said during a meeting with Chinese President Xi Jinping in Beijing later Friday afternoon.
Xi expressed gratitude for Australia's search for the jet, which went missing during a flight from Kuala Lumpur to Beijing on March 8 with 239 people on board, adding China would continue searching for the flight and maintain close communication with Australia.
Separately, Australia's Joint Agency Coordination Center (JACC), which is leading the international search effort, said in a statement that analysis had shown the signal picked up Thursday by an Australian surveillance plane was not related to the missing flight.
A Royal Australian Air Force (RAAF) AP-3C Orion aircraft detected the signal close to where the Ocean Shield was searching.
"The Australian Joint Acoustic Analysis Center has analyzed the acoustic data and confirmed that the signal reported in the vicinity of the Australian Defence Vessel Ocean Shield is unlikely to be related to the aircraft black boxes," JACC chief Angus Houston said in a media release.
Houston said there had been no major breakthrough in the search for the missing jetliner, based on the information currently available.
On the timing of the deployment of an autonomous underwater vehicle, Houston said a decision would be made "on advice from experts on board the Ocean Shield and could be some days away."
The Pentagon said Friday that the U.S. Navy 7th Fleet supply ship Cesar Chavez had joined the international search taskforce.
In the coming days, Chavez is scheduled to resupply Australian naval ships involved in the search, including HMAS Success, HMAS Perth and HMAS Toowoomba.
Meanwhile, Malaysia denied CNN reports that its air force scrambled search aircraft shortly after Malaysia Airlines reported MH370's missing.
The CNN report, citing unnamed sources, claimed that the aircraft were scrambled before the authorities corroborated data indicating the plane turned back westward, and the air force did not inform the Department of Civil Aviation or the authorities conducting search and rescue operations until three days later.
Malaysian Air Force Chief Rodzali Daud said in a statement that CNN's allegation was "totally false."
Malaysian Defense Minister Hishammuddin Hussein's communications team also denied the CNN report on its Twitter account, which was later retweeted by Hishammuddin on his official Twitter account.