Japan on Wednesday unveiled its newest submarine with the aim to boost the country’s maritime security amid China’s growing aggression in the region. According to a report by the Kyodo news agency, the 3,000-ton warship named the Taigei, built by Mitsubishi Heavy Industries Ltd., is scheduled to go into service in March 2022. It is the 22nd vessel in the Maritime Self-Defense Force’s submarine fleet.

This comes a day after the Japan Coast Guard had said that two Chinese patrol ships had illegally entered into the country’s territorial waters off Senkaku islands in the East China Sea on Sunday. The Coast Guard had deployed patrol boats to the area to warn the vessels to leave Japan’s waters. The ships left the area on Tuesday night. The Kyodo news agency reported that the two ships left Japanese waters and sailed in the so-called contiguous zone from 8:19 pm Tuesday after remaining in the waters for a record 57 hours 39 minutes.

This was the longest intrusion into the waters in eight years since Japan’s government purchased some of the Senkaku Islands from a private Japanese owner in 2012, NHK World reported. It further reported that this was the first time since August 28 that the Chinese government vessels entered Japan’s territorial waters, and 18th time this year.

China has been increasing its maritime activities in both the South China Sea and the East China Sea over the past few months, partly in response to Beijing’s concerns over the increasing US military presence in the region because of escalating Sino-US tensions. The intrusions have not only been condemned by the US but have also invited the latter to conduct military drills in the South China Sea.

Kyodo news agency said that under its 2010 National Defense Program Guidelines, Tokyo has set a goal of increasing the number of its submarines from 16 to 22 in light of increasing activities by Beijing in waters near Japan, especially around a group of Japan-administered islands claimed by China in the East China Sea.