The ten-member Association of Southeast Asian Nations (ASEAN) met on Sunday at a historic summit hosted for the first time by Myanmar - formerly known as Burma - in its remote showpiece capital Naypyidaw.

Concerns over a stand-off in the South China Sea between China and Vietnam are likely to put the focus of discussion on longstanding maritime disputes in the region.

Tensions rose this week after China moved a deep-water oil rig into territory near the Paracel Islands also claimed by Vietnam.

Chinese and Vietnamese ships have since been involved in several collisions, with the two communist countries trading accusations of responsibility for aggravating the situation.

The spat has led to bitter anti-China demonstrations in several Vietnamese cities.

Major shipping route

In his opening address at the summit, Myanmar President Thein Sein said "regional and global issues of great concern to ASEAN will be extensively discussed among ourselves," without explicitly mentioning the growing maritime crisis.

On Saturday, ASEAN foreign ministers expressed "serious concerns over the ongoing developments" in a joint statement, while Philippine President Benigno Aquino urged fellow Southeast Asian leaders to confront China's increasing assertiveness in the sea as a threat to regional security.

The South China Sea is a major shipping waterway and is also thought to contain vast energy reserves.

Leaders are also expected to discuss tensions on the Korean Peninsula and the political crisis in Thailand.

Once ostracized

It is the first time Myanmar has hosted the summit, despite being a member for 17 years.

Until recently, concerns about the former junta's human rights record had kept it on the sidelines, but reforms introduced since 2011 under a quasi-civilian regime have improved the country's international standing.

The ASEAN bloc comprises Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanamar, the Philippines, Singapore, Thailand and Vietnam.

Its bi-annual meetings end with declarations on regional issues such as economic and security cooperation.

tj/ipj (Reuters, AFP, AP)