U.S. President Barack Obama was to host leaders of Southeast Asian nations in a special summit opening in California on Monday as the United States has been seeking to drum up international support for pressure on North Korea.

The two-day meeting with the leaders of the 10-member Association of Southeast Asian Nations is part of efforts to further bolster U.S. relations with Asian countries under Obama's trademark "rebalance" or "pivot" to Asia policy in the face of a rising China.

On Feb. 7, North Korea defied international warnings and conducted a long-range missile launch following its fourth nuclear test a month earlier. U.S. officials have said it would be "natural" for this week's summit with ASEAN to address North Korea issues.

During the summit set to take place at the Sunnylands resort in Southern California, Obama is expected to explain the international community's efforts to increase pressure on North Korea and seek ASEAN's support for such efforts, U.S. officials have said.

Ben Rhodes, a deputy national security adviser, said last week that the U.S. has worked with some ASEAN nations to address a range of security challenges related to the North, including counter-proliferation efforts to ensure that Pyongyang is not able to export material that could serve a proliferation purpose.

"We've had good cooperation on that," he said. "Some of these countries have reduced their relations with North Korea, their military-to-military cooperation. So I think we've had some good progress with ASEAN countries on that set of issues."

But the biggest topic for this week's summit is expected to be territorial disputes in the South China Sea between China and Southeast Asian nations, such as the Philippines and Vietnam, amid Beijing's increasingly assertive moves.

Officials said that the first day of discussions will focus on economic issues, such as the Trans Pacific Partnership free trade agreement, while the second day of talks will deal with security matters, such as South China Sea disputes. (Yonhap)