The US Navy said Monday it was sending a black box locator to an area of the southern Indian Ocean being scoured for the missing Malaysian jet, following a cluster of weekend debris sightings.
The navy called the move a "precautionary measure" in case those sightings confirm the location of the aircraft which disappeared on March 8 with 239 people on board.
"If a debris field is confirmed, The Navy's Towed Pinger Locator 25 will add a significant advantage in locating the missing Malaysian aircraft's black box," Commander William Marks, a spokesman for the US Seventh Fleet, said in an e-mailed statement.
The locator system relies on acoustic signals to help find flight recorders -- also known as black boxes -- on downed navy and commercial aircraft to a maximum depth of 20,000 feet (6,000 metres), he added.
However, the statement cautioned that the deployment did not mean the missing jet's location had been confirmed.
"Please note that movement of the Towed Pinger Locator into the region is not an indication that we have confirmed a debris field," it said.
"It's a precautionary measure so that if we do find debris, we'll be ready to deploy the equipment to listen for the black box."
On Monday, a Chinese military plane set off from the western Australian city of Perth at first light to search for "suspicious debris" floating in the remote waters and captured by Chinese and Australian satellite imagery, China's state news agency Xinhua said.
The sighting of a wooden pallet and other debris that may be linked to the Malaysian passenger jet gave the sense Sunday that the hunt was finally on the right track after more than two weeks of false leads and dead ends.
It was reinforced by new French satellite data indicating floating objects in the southern search area.
Australian officials said the pallet, along with belts or straps, was spotted Saturday in a remote stretch of the Indian Ocean that has become the focus of the search -- around 2,500 kilometres (1,500 miles) southwest of Perth.