"All have responsibility that we follow international law and norms on maritime issues as we do in realm of air," Modi told leaders of southeast Asian nations at the 12th India-ASEAN summit here in the Myanmarese capital.
Though Modi did not name any country but the comments may be seen as targeting China which is engaged in maritime territorial disputes with a number of its neighbours, including Japan, Vietnam and the Philippines.
They had stressed the importance of safeguarding maritime security and ensuring freedom of navigation and over flight throughout the region especially in the South China Sea.
During his Japan visit as well, Modi had deplored the "expansionist" tendency among some countries which "encroach" upon seas of others, in oblique comments against China which also has a maritime dispute with Japan over islands in the East China Sea.