A deep sea exploration vehicle searching for the missing Malaysia Airlines flight MH370 sank after colliding with a submerged volcano, The Guardian reported Sunday.

The sonar vehicle, known as a towfish, was said to be missing as the collision with the 2,200-metre mud volcano on Sunday broke the cable attaching it to the Fugro Discovery search vessel, said the agency running the search.

The impact of the collision left the towfish and 4,500m of cable lost on the bed of the Indian Ocean.

On Monday, the Joint Agency Coordination Centre confirmed that Fugro Discovery lost the sonar vehicle deep tow while conducting search activities in the southern Indian Ocean.

“The towfish collided with a mud volcano which rises 2,200 metres from the seafloor resulting in the vehicle’s tow cable breaking. The towfish and 4,500 metres of cable became separated from the vessel and are now resting on the seafloor,” said the agency as quoted in The Guardian.

It was reported that no injuries were sustained by crew.

The centre also believed it will be able to recover the vessel, and that the search for the missing plane continues.

On Saturday, a large piece of metal has been washed ashore in Thailand, promping speculation it might belong to the missing Malaysia Airlines Flight MH370.

The piece of metal, measuring two metres wide and three metres long, has been found off the coast of southern Thailand.

But aviation experts said it was unlikely to belong to Flight MH370 which vanished nearly two years ago while en route to Beijing and believed to have crashed in the Indian Ocean, killing all 239 people on board.

However, Thailand's Department of Civil Aviation (DCA) will despatch two aviation experts to Nakhon Si Thammarat today to further analyse the suspected aircraft debris.