Japenese Prime Minister Yoshihide Suga on Monday agreed with his Vietnamese counterpart Nguyen Xuan Phuc to cooperate on regional issues including the disputed South China Sea (SCS).
Speaking to media in Hanoi, Suga described the pact with Vietnam as a "big step in the field of security". The agreement in principle could see Japan exporting defence equipment and technologies including patrol planes and radar to Vietnam, a rival claimant and vocal critic of Beijing's expansive claims in the resource-rich South China Sea, South China Morning Post (SCMP) report.
According to SCMP, Japan is ramping up pressure on China over the South China Sea.
Suga, who took office last month, said Vietnam was a "cornerstone" of efforts to realise a "free and open Indo-Pacific" and that Japan would contribute to "peace and prosperity in the region", Kyodo News reported.
He also criticised activities in the South China Sea "that go against the rule of law" - a veiled reference to Beijing's assertiveness in the busy waterway, through which a third of global shipping is estimated to pass.
"It is important that all nations involved work towards a peaceful resolution of conflict in the South China Sea without resorting to force or coercion," Suga said during a speech at a university in Hanoi.
Meanwhile, Japenese Defence Minister Nobuo Kishi and his Australian counterpart Linda Reynolds had agreed in Tokyo to strengthen cooperation in the Indo-Pacific, including maritime activities in the South China Sea.
Indo-Pacific region is largely viewed as an area comprising the Indian Ocean and the western and central Pacific Ocean, including the South China Sea.
China's territorial claims in the South China Sea and its efforts to advance into the Indian Ocean are seen to have challenged the established rules-based system.