A deep-sea research sub has been lost in the Kermadec Trench, north east of New Zealand.
The Nereus sub. Photo: Woods Hole Oceanographic Institution
The Nereus went missing while exploring the trench, one of the ocean's deepest spots.
Surface debris was found, suggesting the vessel suffered an implosion as a result of immense pressures where it was operating some 10km down.
The $US8 million robot was built for the Woods Hole Oceanographic Institution in 2008.
''Nereus helped us explore places we've never seen before and ask questions we never thought to ask," said Timothy Shank from the Institution.