Search teams have begun using a towed pinger locator to hunt for the black box of missing Malaysia Airlines flight MH370.

Two ships with locator capabilities are searching a 240km (150 mile) underwater path, in the hope of recovering the plane's data recorder.

Up to 14 planes and nine ships were due to take part in Friday's search.

The plane disappeared on 8 March en route from Kuala Lumpur to Beijing. It was carrying 239 people.

It is believed to have crashed in the southern Indian Ocean, although no confirmed debris has been found from the plane.

The search is being co-ordinated from the city of Perth in Western Australia.

The battery-powered pingers on the plane's black box stop transmitting about 30 days after a crash, giving the searchers now perhaps only a few days to locate it.

'Highest probability'

Angus Houston, head of the Joint Agencies Coordination Centre (JACC) leading the search, said that two ships had "commenced the sub-surface search for emissions from [the] black box pinger".

Australia naval vessel Ocean Shield was using a towed pinger locator from the US Navy, while HMS Echo, which had similar capabilities, was also searching.