Japan opposes any actions that will escalate tensions in the East and South China Seas, Prime Minister Yoshihide Suga said Wednesday as he wrapped up a trip to Vietnam and Indonesia, but he added Tokyo was not aiming at an "Asian NATO" to contain any specific country.

Suga's four-day visit to the two Southeast Asian countries, his first overseas trip since taking office last month, is part of Japan's efforts to bolster ties with key regional countries amid concerns about China's growing assertiveness in the region.

"Japan is opposed to any actions that escalate tensions in the South China Sea. Let me stress anew the importance of all the countries concerning the South China Sea issues not resorting to force or coercion, but working toward peaceful resolutions of the disputes based on international law," Suga told a news conference in Jakarta.