President Duterte unable to attend ASEAN Summits with US President Obama and India PM Modi pic.twitter.com/RFjGb0iF6Q

— Willard Cheng (@willardcheng) September 8, 2016

VIENTIANE - President Duterte was not able to attend the Association of Southeast Asia Nations (ASEAN) summits with India and the United States in this Laotian capital.

Foreign Affairs Secretary Perfecto Yasay represented Duterte instead.

Duterte was also unable to attend the ASEAN-United Nations Summit on Wednesday.

READ: Duterte skips ASEAN-UN meeting with Ban Ki-moon

The meeting would have been another chance for Duterte to meet US President Barack Obama, with whom the foul-mouthed Philippine leader had a spat earlier.

Duterte and Obama already had a brief meeting on Wednesday evening for the ASEAN gala dinner.

SOUTH CHINA SEA ISSUE

The South China Sea issue, which has deeply divided the 10-member bloc, was discussed by Obama during the meet.

The Philippines is a key figure in the South China Sea dispute, as it is the first country to hail China to a United Nations-backed tribunal over the maritime row. It was Duterte's predecessor, Benigno Aquino III, who led the filing of the case against China.

The Hague-based tribunal has since invalidated China's historical claims to the vast sea, a major victory for Manila which Duterte had promised not to ''flaunt."

Duterte has been seeking closer ties with the economic powerhouse China, and some analysts say this could hurt Manila's relations with Washington.

READ: 'Philippines spat plays into China's hands'

Duterte's controversial remarks against Obama underscores the challenges facing the relations between Manila and Washington.

OBAMA: RESPECT SEA RULING

In his opening remarks at the ASEAN-US Summit, Obama insisted that the July ruling of the arbitral court on the South China Sea is binding, and wants to ensure that disputes are resolved peacefully and tensions eased.

"With respect to maritime issues, we'll continue to work to ensure that disputes are resolved peacefully including in the South China Sea. The landmark arbitration in July which is binding helped clarify maritime rights in the region. I recognize this raises tensions but I also look forward to discussing how we can constructively move together to lower tensions and promote diplomacy and regional stability," Obama said.

He also mentioned human rights and cited the parties' commitment to uphold them, as well as other commitments made in the ASEAN-US Sunnylands declaration.

"We have laid out a common vision for the region articulated in the Sunnylands Declaration, an open, dynamic, economically competitive Asia Pacific that respects human rights and upholds a rule-based order. Today we can discuss further how we can advance that vision together," Obama said.

He underscored the importance of the region in the US rebalancing in Asia. He said the US will continue to work with the region to promote innovation, entrepreneurship, people-to-people exchange, and boost other areas of cooperation such as fighting terrorism and epidemics.

"Together were expanding cooperation to address transnational threats. We will stay vigilant in combating terrorism including in Southeast Asia where we have very strong partnerships with many of you," Obama said.

He called on the region to enforce the Paris climate change agreement as soon as possible, saying the US is willing to help economies transition to cleaner ones that do not impinge on but help spur development and opportunities, as well as help strengthen resilience against climate change.