Plane signals still unconfirmed

Prime Minister Tony Abbott said search teams with the Australian-led operation in the southern Indian Ocean were racing to gather as many signals as possible on Friday to determine an exact resting place for the Malaysian Airlines Boeing 777.

"We have very much narrowed down the search area and we are very confident the signals are from the black box," Abbott said in Shanghai on Friday. "We are hoping to get as much information as we can before the signal finally expires," he added.

The Royal Australian Navy has used planes to drop buoys dangling listening devices into the water in an effort to pinpoint any wreckage. All 239 people on board, two-thirds of them Chinese, are believed to have died.

If the signals are confirmed, this would be the fifth underwater "ping" detected in the search for the plane, which disappeared while en route from Kuala Lumpur to Beijing on March 8. However, experts remain skeptical the signals are coming from MH370.

Search chief: 'Unlikely'

Despite Prime Minister Abbott's assertion, the Perth-based Joint Agency Coordination Centre (JACC) announced on Friday that initial analysis had determined that the signal picked up on Thursday afternoon by a P-3C Orion surveillance plane did not appear to be linked to aircraft beacons.

The Orion had flown close to the area where two signals came from at the weekend, and the Australian ship Ocean Shield - a vessel equipped with a US Navy towed pinger-locator patrolling the ocean 2,200 kilometers (1,400 miles) northwest of Perth - picked up two more blips on Tuesday.

"Further analysis continues to be undertaken," JACC chief Angus Houston said on Friday. "Today Ocean Shield is continuing more focused sweeps with the towed pinger-locator to try and locate further signals that may be related to the aircraft's black boxes," Houston added. "It is vital to glean as much information as possible while the batteries on the underwater locator beacons may still be active."

Fourteen planes and 13 vessels are involved in the operation. The JACC announced that it had reduced the search area for Friday to two zones totaling about 47,000 square kilometres.

Houston said Friday that a decision to deploy a submersible sonar device "could be some days away."

mkg/jm (Reuters, AFP, AP)