A recently-refurbished Indian submarine exploded and sank early Wednesday in a dock

A recently-refurbished Indian submarine exploded and sank early Wednesday in a dock in Mumbai, leaving rescuers scrambling to find 18 sailors who were on board.

The diesel-electric INS Sindhurakshak had been returned by Russia less than a year ago after a major refit and was totally submerged after the accident, navy sources said.

The NDTV channel showed grainy and shaky footage of the fierce explosion which lit up the sky at the naval dockyard shortly after midnight.

The navy ordered a board of inquiry into the explosion.

The accident comes just days after New Delhi trumpeted the launch of its first domestically-produced aircraft carrier and the start of sea trials for its first Indian-made nuclear submarine.

India has been expanding its armed forces rapidly to upgrade its mostly Soviet-era weaponry and react to perceived threats from regional rival China.

Source AFP