New Delhi, Aug 31 - India Monday expressed concern over Pakistan illegally modifying US-supplied Harpoon anti-ship missiles to hit land-based targets, saying this was 'against India's national interest'.

'This is the danger of proliferation that we have been mentioning to America that whatever you have given to Pakistan will not be used in self defence. This (modification of the Harpoon missile) has nothing to do with self defence and is against India's national interest,' said outgoing Indian Navy chief Admiral Sureesh Mehta, who retired Monday.

A US media report Sunday said that Pakistan had illegally modified the Harpoon missiles to allow them strike land-based targets, making them a potential threat to India.