Prime Minister Yoshihide Suga on Monday voiced "grave concerns" over China's aggressive actions in surrounding waters in phone talks with Indian counterpart Narendra Modi.

Suga relayed Tokyo's worries about Beijing's "intensifying unilateral attempts to change the status quo" in the East and South China seas, including the recent introduction of a law allowing its coast guard to use weapons against ships it views as intruding into its territory, according to the Foreign Ministry.

The leaders affirmed the importance of Japan and India cooperating to realize a "free and open Indo-Pacific" region, the ministry said, along with other countries including the United States and Australia.

The four countries, also known as the Quad, have been bolstering ties as a counter to China's growing economic and military clout.

Beijing is embroiled in a number of territorial disputes, including in the East China Sea over the Japanese-administered Senkaku Islands, which it claims and calls Diaoyu. It has also continued the militarization of artificial islands in the disputed South China Sea despite an international ruling in 2016 against its claims.

During their 25-minute call, Suga and Modi agreed to work together to fight the coronavirus and welcomed progress on plans to build a 500-kilometer high-speed rail corridor in India using Japanese technology and funding.

Suga also touched on bilateral cooperation in areas including cybersecurity, decarbonization, 5G networks and supply chain diversification, the ministry said.

The leaders agreed to rearrange Suga's trip to India when the situation allows. His visit was originally slated to take place during the Golden Week holidays beginning in Japan this week but cancelled amid a rise in infections at home and abroad.

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