Taiwan has launched its first domestically assembled submarine, a significant step towards bolstering its naval defenses against increasing threat from Xi Jinping.

The unveiling comes against a backdrop of increased Chinese military activity in the waters surrounding Taiwan. The island nation is ramping up efforts to modernize its aging fleet in response to potential threats from China’s People’s Liberation Army, reported Bloomberg

The prototype named “Hai Kun” underwent its first sea trial on Thursday at the CSBC Corp.’s Kaohsiung dockyard. This is part of a multibillion-dollar program to develop eight new vessels.