As Japan steps up to counter China's growing influence in Asia Pacific, Tokyo's efforts may not be as effective without "commitment" from the United States — a situation which may disadvantage regional countries as well as Washington, an expert told CNBC.
Tokyo's efforts to counter Beijing's influence in Asia have to be balanced with the U.S. asserting its economic commitment to the region, said Stephen Nagy, senior associate professor in the department of politics and international studies at the International Christian University in Tokyo.
"Japan can't just do this alone. It just doesn't have the resources ... It needs the economic (support) as well as the security that the United States can provide to the region," Nagy told CNBC on Tuesday.
Japan agreed to deepen cooperation with Southeast Asia during the 10th Mekong-Japan summit held in Tokyo on Tuesday. The meeting is part of Japan's efforts to boost its presence in the region as China's political and economic clout grows through infrastructure projects such as the Belt and Road Initiative (BRI).