Prime Minister Hun Sen left for Tokyo on Thursday, for discussions with one of the nation’s top donors about development within the region.

Japan is hosting a two-day summit between Mekong countries, starting Friday, to discuss development of infrastructure, human resources and others, officials said.

Sri Thamrong, an adviser to Hun Sen, said the summit will also focus on “natural disasters, disaster management, climate change, environmental protection and the prevention of infectious diseases, “as well as development and stability in the region.”

The Japan-Mekong Region Partnership Program seek to expand Japan’s assistance to Cambodia, Laos and Vietnam, as well as the region overall, over the next three years, totaling $40 million.

Mekong countries include Burma, Cambodia, Laos, Thailand and Vietnam.

Before departing, Hun Sen told a group of editors from Japan’s Kyodo news service that Tokyo had played a key role in peace development in Cambodia and economic development in the region.

Overall, Japan has contributed more than $1.7 billion in aid to Cambodia.