Philippine President Rodrigo Duterte is presiding over the East Asia Summit (EAS) on Monday afternoon.
The event is held every year, coinciding the Association of Southeast Asian Nation (ASEAN) Summit.
In his opening remark, Duterte stressed the need for world leaders to mitigate the effects of climate change.
He also said nations together must deal with the threat of terrorism.
"Cooperation at the highest levels has a big impact on regional security," he told world leaders.
EAS brings together 18 states including the United States, China, India, Russia, Australia, New Zealand, Japan and South Korea as well as the 10 members of the ASEAN.