India and Japan are taking steps to deepen defence cooperation, a move likely to add to China's unease at a time of rising tensions between Tokyo and Beijing over a chain of disputed islands in the East China Sea.
Tokyo has for the first time assigned a naval attaché to its embassy in New Delhi, signalling a desire to broaden its maritime relationship with India.
This follows an Indian initiative to deepen naval engagement with Japan. In January, India brushed aside Chinese concerns and invited Japan to join the Indo-US joint naval exercise Malabar in the Pacific later this year.
China had lodged a formal protest when Japan was invited to take part in this exercise in 2007.
Japan has posted Captain Shusuke Takahashi as its naval attaché to India. "Formerly, there was only one defense attaché from the Japan Ground Self-Defense Force. Now, there are two attaches," a Japanese official said on Friday.
The appointment comes at a time when Japan is hoping to conclude a deal to supply nine ShinMaywa US-2 amphibious aircraft to the Indian Navy, Tokyo's first overseas military sale since it imposed a weapons export ban in 1967. The deal is worth more than Rs 6,000 crore.
Prime Minister Narendra Modi and his Japanese counterpart Shinzo Abe, who share a good personal rapport, could take the bilateral relationship to a new level. Modi is one of the only three people Abe follows on the micro-blogging site Twitter.
Modi is expected to visit Japan after the ongoing Budget session of Parliament ends on August 14.