The U.S. looked to highlight the positive elements of the U.S. and Philippine relationship on Tuesday following comments made by new Philippines President Rodrigo Duterte that resulted in the U.S. calling off a bilateral meeting between the two nations.
Duterte sought to defuse a row with the United States on Tuesday, voicing regret for his perceived insult of President Barack Obama.
READ: Duterte 'regrets' comments vs. Obama, hopes to resolve spat
The tiff between the two allies overshadowed the opening of a summit of East and Southeast Asian nations in Vientiane, Laos.
It also soured Obama's last swing as president through a region he has tried to make a focus of U.S. foreign policy, a strategy widely seen as a response to China's economic and military muscle-flexing.
Obama's deputy National Security director Ben Rhodes told reporters the U.S-Phillippine relationship remained "rock solid." Rhodes said "people should certainly expect that our very close working relationship with the Philippines is going to be enduring."
Ben Rhodes said the focus on Duterte's comments leading into the summit had not created a constructive environment for a bilateral meeting.
"All of the attention frankly was on those comments, and therefore not on the very substantive agenda that we have with the Philippines," he told reporters.
Officials from both countries said there would be no formal meeting rescheduled in Laos but a short conversation between the two presidents was possible.
Instead of the Duterte meeting, Obama held talks with South Korean President Park Geun-hye, a day after North Korea fired three medium-range missiles into the sea. He urged a full implementation of sanctions against North Korea, adding that the missile test demonstrated the threat that Pyongyang posed.
Obama is also likely to hold an unscheduled meeting in Laos with Japanese Prime Minister Shinzo Abe to discuss North Korea, Rhodes said. He said Washington needed to maintain a sense of urgency within the international community on sanctions against Pyongyang.
Diplomats say strains with longtime ally the Philippines could compound Washington's difficulties in forging a united front with Southeast Asian partners on the geostrategic jostle with Beijing over the South China Sea.
Rhodes also discussed the need to focus on North Korean sanctions following news of another missile test.
"We have to be very vigilant in sanctions enforcement and we have to maintain the sense of urgency among the international community," Rhodes said.
Obama, the first sitting U.S. president to visit Laos, said on Tuesday he wanted to address the legacy of U.S. bombing during the Vietnam War. He announced that Washington would provide an additional $90 million over three years to help clear unexploded ordnance, which has killed or wounded over 20,000 people.
But the unusually open tensions between the United States and the Philippines, its former colony, threaten to overshadow the Association of Southeast Asian Nations (ASEAN) and East Asia Summits in Laos, which run until Thursday.