Australian officials remain cautious about satellite images that may show debris from MH370, although the possibility is strong enough that they have focused the southern Indian Ocean search on the new finding.

“It is a lead, and probably the best lead we have right now,” says John Young, the emergency response division general manager for the Australian Maritime Safety Authority (AMSA). However, he stresses that it may still turn out to be unrelated to the search for the Malaysia Airlines Boeing 777. Large items such as shipping containers are sometimes found in the ocean, but the size of the debris in the images makes it “interesting,” Young said during a press conference today.

Two large objects are shown in the satellite images, about 2,500 km (1,550 mi.) southwest of Perth, which is in Western Australia. Young admits they are “relatively indistinct,” although experts examining the pictures described them as “credible” sightings. The objects are of “reasonable size,” and appear to be awash, says Young. One is 24 meters (79 ft.) long, the other five meters. The pictures are not precise enough to distinguish windows or markings, although more detail may emerge when other satellites are directed to take high-resolution images “in due course.”

Australian Prime Minister Tony Abbott first announced the satellite images during a parliamentary session. Abbott stresses that the objects will be difficult to find and may not be aircraft debris.

A Royal Australian Air Force (RAAF) Lockheed P-3 aircraft was immediately diverted to try and locate the objects, and another three followed. These included an Australian P-3, a New Zealand P-3, and a U.S. Navy Boeing P-8 Poseidon. An RAAF Lockheed C-130 was tasked with dropping marker buoys to determine current and drift. It takes about four hr. for a P-3 to fly to the site of the satellite images, leaving two hr. of search time. The search was stopped for the night, to resume March 21.

Australian navy warship HMAS Success is en route to the area, but is still some days away. It is equipped to recover debris. A Norwegian cargo ship is currently on the scene, and has been asked to look for aircraft remains.

In a subsequent press conference in Kuala Lumpur, Malaysian officials said that the southern search includes 25 aircraft, 18 ships and six helicopters, from a broad range of countries.