Opposition continues stepping up pressure on Defence Minister AK Antony, demanding accountability and answers for the mishap onboard the INS Sindhuratna. The opposition has made it clear that the security of the nation is a serious issue. INS Sindhuratna was at sea off Mumbai for routine training and workup (inspection) in the early hours of Feb 26 when smoke was reported in the sailors' accommodation, in compartment number three, by the submarine. Two Navy officials were killed and seven sailors injured in the mishap.