Southeast Asian leaders are meeting at an annual forum that will focus on the civil war in Myanmar and territorial tensions in the South China Sea, two challenges that have long tested the bloc's credibility.

Rising tensions in the disputed South China Sea will also be on the agenda at the gathering of the Association of Southeast Asian Nations in Laos.

VIENTIANE, Laos (Reuters) -Southeast Asian leaders met in Laos on Wednesday for a summit expected to seek ways address the worsening civil war in Myanmar, with Thailand calling for heightened engagement ahead of a planned election by the country's embattled military rulers.