New Delhi, July 25 - Marking a quantum leap in India's shipbuilding capabilities, Prime Minister Manmohan Singh will Sunday launch the country's first indigenously designed and built nuclear-powered attack submarine in Visakhapatnam, an official said.

'The prime minister will launch the vessel. The function will also be attended by the defence minister (A.K. Antony),' a senior defence ministry official told IANS Saturday, requesting anonymity.

The submarine is currently housed in a dry dock, which will be flooded with sea water to mark the launching ceremony.

July 26 is annually commemorated as Kargil Victory Day to mark the Indian Army's success against Pakistani intruders who had occupied the area in Jammu and Kashmir in 1999.

The submarine will be commissioned in the Indian Navy as INS Arihant, which translates as 'destroyer of enemies', after extensive outfitting and sea trial. It is the first of three such vessels to be built in the country. Hitherto, submarines have been built here under licence from their foreign designers.

Earlier this year, Antony had lifted the cloak from India's secret submarine project, saying: 'Things (the project) are in the final stage. Some years back, there were some bottlenecks in terms of supply of parts. It is over now. We will announce it (the vessel's launch) whenever it is ready.