A deep-sea drone completed its first full scan of the seabed in the remote Indian Ocean, the team looking for Malaysia Airlines flight MH370 said on Thursday, as an air and surface search became less likely to yield results.

Footage from a US navy drone is becoming the most important tool for a multinational team searching for MH370, which vanished on March 8 with 239 people on board, including 154 Chinese passengers, Reuters reported.

A series of "pings" recorded this month have led searchers to the remote stretch of ocean west of the Australian city of Perth, in the belief that the signals may have come from the plane's black box recorders.