Some quarters in the Indian defense establishment is reportedly disturbed by docking of a Chinese submarine in Colombo on a long-range deployment patrol earlier this month. They see it as yet another indicator of the ever-increasing forays of the People's Liberation Army-Navy (PLA-N) in the Indian Ocean Region (IOR), Indian media reports say.

The PLA-N is said to be transforming from a "green-water" force used to operating close to its own shores into a potent "blue-water" force, one with "long legs".

Though the Indian Navy has been tracking the increased activity of Chinese warships in the IOR, including submarines quietly on the prowl in the Bay of Bengal, this is a rare instance of a PLA-N submarine openly berthing in the region that India considers its "own strategic backyard", Times of India said today.

The diesel-electric Type 039 "Song-class" was at the Colombo International Container Terminal, which has been funded by China, from September 7 to 14, just ahead of Chinese President Xi Jingping's visit to Sri Lanka,

Sri Lanka and nearby Maldives has shown enthusiasm for China's new Maritime Silk Route plan in the IOR.

The Chinese government, on its part, said the submarine had only made a replenishment stopover in Sri Lanka on way to the Gulf of Aden for escort and anti-piracy operations, as was the "common practice" for navies around the world.

Despite these views reportedly coming from certain members in the defense establishment, China and India have been developing new friendships. President Xi visited India following his trip to Sri Lanka, landing in Narendra Modi’s home state of Gujarat on the Indian PM’s 64 th birthday.