A ship operated by exploration firm Ocean Infinity arrived at the search area in the Indian Ocean yesterday and launched the drones, said Malaysia's Department of Civil Aviation director-general Azharuddin Abdul Rahman.
"The vessel Seabed Constructor has arrived at the search area and commenced the search operation," he said in a statement.
The jet disappeared in March 2014 with 239 people -- mostly from China -- on board, en route from Kuala Lumpur to Beijing.
Ocean Infinity struck a deal with the Malaysian government to restart the hunt on a private basis and will only be paid if it finds the jet or its black boxes. It stands to make up to USD 70 million if successful.
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The new search zone is an area of about 25,000 square kilometres in the southern Indian Ocean, north of the former search area. The hunt will last a maximum of three months.
If it is found within the first 5,000 square kilometres, the firm will receive USD 20 million. The amount rises gradually to a maximum of USD 70 million if the jet is found outside the 25,000 square kilometre search zone.
The ship conducting the hunt is a Norwegian research vessel carrying 65 crew, including two members of the Malaysian navy as the government's representatives.
It is using eight autonomous drones, equipped with sonars and cameras, that will scour the waters for wreckage and can operate in depths up to 6,000 metres (20,000 feet).
Only three confirmed fragments of MH370 have been found, all of them on western Indian Ocean shores, including a two-metre wing part known as a flaperon.