Objects spotted may be debris from Malaysia Airlines Flight 370

 An aircraft in the area detects radar hits of “significant size,”

Search crews are scouring the southern Indian Ocean today after two objects that may be related to the missing Malaysia Airlines flight were spotted by satellite, officials said Thursday.

Officials described the sighting as the best lead at this stage in the investigation – saying four aircraft and one merchant ship are heading to the region off the coast of Australia.

Satellite1_small Objects spotted may be debris from Malaysia Airlines Flight 370

A US Navy P-8 Poseidon is involved with the search, occurring about 1,500 miles off of Australia’s coast. ABC News’ David Wright was the only TV reporter on board the flight.

Crew members told ABC News that they received radar hits of “significant size,” indicating something lurking below the water’s surface — but Commander William Marks, spokesman for the US Navy’s 7th Fleet, later said the radar return was typical, and not connected to the missing plane.

Australia’s government released satellite images of the possible objects today, described as the best lead at this stage in the investigation.

The updates have been deemed “credible enough to divert resources to this area,” said John Young with the Australian Maritime Safety Authority’s Emergency Response Division. The largest of the objects spotted on satellite is about 78 feet long, he said.

“This is a lead, it is probably the best lead we have right now,” Young said.

Despite the development, officials are stressing caution, saying the objects might not be related to Flight 370.

Earlier, American and British aviation officials refined satellite signals from the missing plane, creating two possible flight paths that dramatically narrowed the scope of the search.

The plane was carrying 239 people when it disappeared on March 8.