An Indian navy spokesman says a sailor and a civilian worker have been killed by a toxic gas leak in the sewage plant on board India's aircraft carrier.

Capt. D.K. Sharma says the Russian-built "INS Vikramaditya" carrier has been undergoing maintenance work at a naval base in southern India.

India's navy has been plagued by accidents in recent years that have raised questions about safety and Navy chief Adm. D.K. Joshi resigned in 2014 to take responsibility for a series of accidents.

One of the the navy's Russian-made diesel-powered submarines, the INS Sindhurakshak, caught fire after an explosion and sank at its home port in Mumbai in 2013, killing all 18 sailors on board.