India says nuclear submarine makes first patrol, Modi warns against 'misadventure'

India said on Monday its first domestically built nuclear-powered submarine had recently completed a "deterrence patrol", giving it the capability to fire nuclear weapons from land, air and sea in the event of any "misadventure" by enemies.

With nuclear-armed China to its north and nuclear-armed Pakistan to its west - both of which India has fought wars with - India's nationalist prime minister, Narendra Modi, said the INS Arihant was a "fitting response to those who indulge in nuclear blackmail".

He did not elaborate.