Japan and US agree to strengthen alliance amid geopolitical tensions

ASEAN Summit in Phnom Penh

TOKYO (Reuters) - Japan's Prime Minister Fumio Kishida and U.S. President Joe Biden agreed at a meeting on Sunday to strengthen their countries' alliance amid shared concerns over a rise in geopolitical tensions.

The two met on the sidelines of a summit of the Association of Southeast Asian Nations (ASEAN) and discussed the conflict in Ukraine, repeated missile launches by North Korea, and tensions in the South and East China Seas, said a statement from the Japanese Ministry of Foreign Affairs.

"We agreed to strengthen the deterrent strength and effectiveness of the U.S.-Japan alliance amid mounting challenges to the security of the region," Kishida told reporters after the summit.

"We reaffirmed that unilateral attempts to change forcefully the status quo is unacceptable, and confirmed that Russia's threats with nuclear power cannot be tolerated," he added.

Kishida and Biden also held trilateral talks with South Korean President Yoon Suk-yeol to discuss threats from North Korea after their summit, before heading to Indonesia's Bali to attend the Group of 20 (G20) Summit.

Japan and the United States also share concerns over the rise of China. Earlier, Biden told Asian leaders that U.S. communication lines with China would stay open to prevent conflict. He is due to hold his first meeting in person since becoming U.S. leader with Chinese President Xi Jinping in Bali on Monday.

(Reporting by Sakura Murakami; Editing by Gareth Jones)