Leaders of the 10-member Association of Southeast Asian Nations – ASEAN – are gathered in Phnom Penh for a two-day summit that is expected to deal with simmering maritime disputes and a scheduled North Korean rocket launch.

Host President Hun Sen focused on economic issues in his opening remarks Tuesday, urging the participating countries to work to narrow the gap between the region's richest and poorest countries.

“Within the region, although the development gap among ASEAN members has been noticeably narrow, it is still huge. This requires to double our efforts to promote further growth and improve equitable distribution of the fruits of growth at both the national and the regional among member countries.”

The official agenda stresses talks on ASEAN's goal of developing a European-style single market within the next three years. But several of the participants have acknowledged the leaders will not be able to avoid discussions on pressing security issues.

The Philippines, Vietnam, Malaysia and Brunei all claim parts of the potentially resource-rich South China Sea, putting them at odds with Beijing, which claims all of the 3.5 million-square-kilometer waterway. The Philippines and Vietnam have both accused Chinese vessels of intruding into their exclusive economic zones and disrupting oil exploration activities.

Manila has called for a summit of nations with claims on the South China Sea in order to reach an agreement on the use of the seas.

Meanwhile, several ASEAN members have raised concerns about North Korea's planned rocket launch this month. Pyongyang says the rocket will place a weather satellite into orbit, but the United States and other nations say the real purpose of the launch is to test a missile that could deliver a nuclear weapon.

During a preliminary meeting Monday, ASEAN foreign ministers praised Burma over its handling of parliamentary by-elections that saw democracy leader Aung San Suu Kyi win her first seat in parliament. Her National League for Democracy party won at least 40 of the 44 seats it contested in the April 1 balloting.

ASEAN comprises Brunei, Cambodia, Indonesia, Laos, Malaysia, Burma, the Philippines, Singapore, Thailand and Vietnam.