TOKYO -- The leaders of Japan and five Southeast Asian countries that share the Mekong River on Tuesday agreed to adopt a new policy that pushes forward more than 150 projects in the Mekong region using official development assistance from Japan.

During a summit in Tokyo, the leaders of Thailand, Vietnam, Cambodia, Laos and Myanmar also confirmed that they will support the "free and open Indo-Pacific strategy" being promoted by Japanese Prime Minister Shinzo Abe and U.S. President Donald Trump. This strategy is seen aimed at countering China as it expands its influence throughout Southeast Asia.

As for the ODA projects, dubbed "Tokyo Strategy 2018," they will focus on three main areas -- effective connectivity, people-centered societies as well as environment and disaster management."

At the summit, the leaders enumerated some of the infrastructure projects, including the expansion of airport facilities in Laos and road construction in Myanmar. In a joint statement, they also listed non-infrastructure types of assistance, like upgrading postal services and using information technology to improve health care.

The new policy revises a similar agreement compiled in 2015.

Mekong region leaders and Japanese Prime Minister Shinzo Abe discuss how to further develop the region during the 10th Japan-Mekong Summit Meeting at the Akasaka Palace in Tokyo on Oct. 9. (Photo by Wataru Ito)

Southeast Asia is currently awash in Chinese investments, part of President Xi Jinping's ambitious Belt and Road Initiative.

Japan is trying to differentiate its aid by focusing on human resource and environmental protection assistance, as well as financial aid. Another goal is to bring quality infrastructure investment to the region.

During the summit, the leaders also discussed issues related to the South China Sea, where China is expanding its military presence and reinforcing its claims to disputed islands and maritime rights.

Though the leaders did not single out China, the joint statement released after the summit says they took "note of some concerns over the situation in the South China Sea including land reclamation projects and activities in the area, which have eroded trust and confidence, increased tensions and may undermine peace, security and stability in the region."

For years now, China has been building islands in the sea's shallow waters and outfitting them with military installations.

At a joint news conference held at the Akasaka Palace, the state guesthouse, Abe said, "[The Japanese government] will use public assistance such as ODA as well as overseas investments and loans to promote private sector investment in the region."

The first Japan-Mekong summit took place in 2009 as Japan sought to help develop a geographically crucial Asian region. The summits are held annually, and this was the first time in three years for Japan to host the event.