A Japanese submarine has joined a naval drill in the South China Sea for the first time, the country’s Defense Ministry said on Monday. Submarine ‘Kuroshio’ took part in the exercise on Thursday with other Japanese warships, including the ‘Kaga’ helicopter carrier, which is on a two-month tour of southeast Asia and the Indian Ocean, Reuters reports, citing a ministry spokesman. The move is seen as an expansion of Japanese activity in the disputed waterway, which is claimed by China and other nations. It is the first time that a Japanese submarine has conducted drills there. The exercise, which involved the submarine trying to evade detection, was conducted away from island bases built by China to push its claims in the strategically important sea. The Foreign Ministry in Beijing said that China “urges the relevant external country to respect the efforts made by regional countries to resolve the South China Sea issue through talks.”