Tokyo (AFP) - Japan on Saturday pledged $6.1 billion in financial aid to the "Mekong Five" countries as it pushes infrastructure exports and courts influence in a region where rival China has an increasing presence.Prime Minister Shinzo Abe unveiled the pledge at a summit with his counterparts from Cambodia, Laos, Myanmar, Thailand and Vietnam -- fast-growing economies through which the lower section of the Mekong river flows."Japan will implement support worth around 750 billion yen ($6.1 billion) in official development assistance for the next three years," Abe told a news conference following the seventh annual Japan-Mekong summit."The Mekong region, which has vast demand for infrastructure, is one of our most important areas," Abe said."Japan will contribute to infrastructure development of the region in both quality and quantity," he added.