Japan and Southeast Asian countries agreed Saturday to strive for freedom of movement in the skies, in the first major gathering of the continent's leaders since China ramped up regional tensions with a controversial air defence zone. The cautious show of support for Tokyo in its bitter row with Beijing came as Japan pledged $20 billion in aid and grants for the region. At a summit in Tokyo, Japanese Prime Minister Shinzo Abe and the leaders of the Association of Southeast Asian Nations (ASEAN) "agreed to enhance co-operation in ensuring freedom of overflight and civil aviation safety". The statement will be seen as a mild regional rebuke for China, which has sovereignty disputes with Japan and with four members of the bloc, and has been repeatedly accused of intimidation and coercion. The gathering also offered encouragement for Abe's more muscular military stance, which some see as a necessary balance to the rising might of China, and which the communique described as a "proactive contribution to peace". "The ASEAN Leaders looked forward to Japan’s efforts in contributing constructively to peace, stability, and development in the region," the statement said. China and South Korea frequently invoke the horrors of the last century in warnings against a more engaged Japanese military, but Tokyo's relations with Southeast Asia -- much of which it also brutally invaded -- are less coloured by history. The endorsements for Japan came at the end of a special summit to mark its 40 years of ties with ASEAN, which saw Tokyo promise two trillion yen for the region over five years. The meeting was the first significant gathering of Asian leaders since China declared an Air Defence Identification Zone over the East China Sea last month, including the airspace above the Tokyo-administered Senkaku Islands, which Beijing claims as the Diaoyus. At the time, Beijing said all aircraft entering the zone have to submit flight plans and obey orders issued by Chinese authorities, in an announcement that was widely criticised as inflammatory, and immediately flouted by Washington, Seoul and Tokyo. That came after more than 12 months of confrontations between Japanese and Chinese coastguards in the seas near the islands, as well as forays by military and paramilitary planes, and shows of strength by naval vessels. Some fear the ADIZ in the East China Sea is a forerunner to a similar zone in the South China Sea, which Beijing claims almost entirely. The summit and Japan's cash pledge crowns a year of courting by Abe, who has visited all 10 countries in the grouping at least once since he came to power last year, always with one eye on wresting back influence in the region from China. "Japan and ASEAN agreed to promote further economic cooperation," Abe told reporters. "We welcomed the substantive agreement in the area of investment and services under the Japan-ASEAN comprehensive economic partnership." On Friday, Tokyo boosted currency swap deals with Indonesia and the Philippines, as well as renewing one with Singapore. The deals give governments room to manoeuvre in times of economic stress because they can be tapped as a supply of liquid assets -- usually US dollars -- if normal currency markets seize up. Tokyo's show of financial largesse marched hand-in-hand with a push by Japanese diplomats for a forceful communique, although they acknowledged that an explicit reference to China was always going to be hard for countries in Beijing's immediate orbit whose economies are so dependant on their giant neighbour. The Philippines, Vietnam, Malaysia and Brunei all have their own disputes with China over territory in the East China Sea, and are thought to be receptive to Japanese overtures. But all 10 members of the bloc, which also includes Cambodia, Indonesia, Laos, Myanmar, Singapore and Thailand, have to tread a fine line to avoid irritating China, whose vast economy is vital to the region. Abe's charm offensive has also been aimed at drumming up business for Japan's infrastructure-makers, with the prime minister keen to boost exports and help give the domestic economy a kick after years of lassitude.