The Australian vessel Ocean Shield has detected a separate acoustic signal in its current search location in the southern Indian Ocean, and is investigating whether it is related to the missing Malaysian airliner.
The Joint Agency Coordination Centre made the announcement on Sunday, as Australia said that planes and ships were also being deployed to another area where a Chinese vessel detected signals consistent with a black box beacon.
Royal Australian Air Force assets were sent to assist in further examining the signals reported by a Chinese ship last Saturday, said Angus Houston, head of the agency leading the search.
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"HMS Echo and Australian Defence Vessel Ocean Shield are also being directed to join Haixun 01 as expeditiously as possible to assist with either discounting or confirming the detections," he said.
The detected pulse signals, also referred to as "pings", were at least 300 nautical miles from each other.
Australia is coordinating the search for the Flight MH370 which went missing on March 8 with 239 people on board.
Beacons in the black boxes emit "pings" so they can be more easily found, but the batteries last for only about a month.
"This is an important and encouraging lead but one which I urge you to continue to treat carefully, we are working in a very big ocean and within a very large search area," Houston added.
On Saturday, the Chinese ship Haixun 01 that is part of the multinational search effort detected a "pulse signal", China's official news agency reported.
The report said it was not established whether that the signal was related to the missing jet, but Australia said the signals are consistent with those of an aircraft black box.
Malaysia's civil aviation authorities said they are verifying the report. So far, no trace of the Boeing jetliner has been found.
In the Malaysian capital Kuala Lumpur on Sunday, relatives of the Chinese and Malaysian passengers held a special service to praying for the safe return of their loved ones.
A multinational team is desperately trying to find debris floating in the water or faint sound signals from the data recorders that could lead them to the missing plane and unravel the mystery of its fate.
Finding floating wreckage is key to narrowing the search area, as officials can then use data on currents to backtrack to where the plane hit the water, and where the flight recorders may be.
Officials have said the hunt for the wreckage is among the hardest ever undertaken, and will get much harder still if the beacons fall silent before they are found.
"Where we're at right now, four weeks since this plane disappeared, we're much, much closer,'' said aviation expert Geoffrey Thomas, editor-in-chief of AirlineRatings.com.
"But frustratingly, we're still miles away from finding it. We need to find some piece of debris on the water; we need to pick up the ping.''
If it does not happen, the only hope for finding the plane may be a full survey of the Indian Ocean floor, an operation that would take years and an enormous international operation.