The incident reinforced the assessment in the country of an increasing Chinese presence and interest in the Indian Ocean Region and the Bay of Bengal in the recent past.

The ship was detected nearly four months ago in the international waters and may have been used to track Indian missiles tests and movement of other aircraft and warships in the region, Navy sources said here today.

The Navy warships could not take any action against it as it was not in Indian territorial waters but kept a close watch on its activities there, they said. "In the coming years, the presence of Chinese ships will increase around Bay of Bengal and Indian Ocean with the inclusion of their aircraft carrier," defence analyst Commander Sunil Chauhan (retd) said.

In the recent years, the Chinese Navy's presence has increased in the Bay of Bengal and the Indian Ocean, which it says is to protect its business interests there. After the increased activity of the Chinese Navy in the in the early part of the decade, India started fortifying its presence and preparedness in the Andaman and Nicobar Islands by deploying a new tri-services command there.

In a phased-approach, India also plans to beef up its force-levels in the islands which include the ramping of army, navy, air force and coast guard infrastructure, including a radar network.

The plans also include deployment of Su-30MKI aircraft, extending the length of existing runways for heavy transport aircraft operations, increasing the strength of personnel and amphibious warfare capabilities.