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.

WASHINGTON (Reuters) - Secretary of State Antony Blinken will represent the United States at the Association of Southeast Nations (ASEAN) summits in Laos this week and expects to discuss human rights in Myanmar, China's "irresponsible" behavior in the South China Sea and Ukraine, the top U.S. diplomat for East Asia said on Tuesday.

By Panu Wongcha-um 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.