The threats of terrorism, the North Korea crisis and maritime tensions loomed large for leaders of Asean's 10 nations and key partners yesterday as they began a series of meetings and called for greater resolve to address these challenges.
Their host, Philippine President Rodrigo Duterte, set the tone in his opening remarks as he spoke of the five-month battle with extremists who had seized the southern city of Marawi and sought to turn it into a province of the Islamic State in Iraq and Syria (ISIS) terror group.
"Terrorism and violent extremism endanger the peace, stability and security of our region because these threats know no boundaries," he said. More than 1,000 people were killed in the conflict and about 400,000 people displaced.
Fellow leaders, including Singapore Prime Minister Lee Hsien Loong, called for greater collaboration to counter terrorism, saying it "remains a serious, acute and continuing threat for the region".
As ISIS loses ground in the Middle East, it is calling on supporters to conduct lone-wolf attacks, and South-east Asia will soon see an increased flow of returning fighters.
"We must continue to be vigilant and pursue deeper cooperation in counter-terrorism," said PM Lee.
The Philippines, Indonesia and Malaysia are already holding joint maritime and air patrols in the Sulu Sea, but experts have said more needs to be done to stem the flow of militants and terror funding by sharing intelligence and resources.
Mr Duterte also cited the problems of piracy and drug trafficking, saying: "Piracy and armed robbery in the seas put a dent on our growth and disrupt the stability of both regional and global commerce."
Touching on the "menace of the illegal drugs trade", he said it "continues to endanger the very fabric of our society".
The issue of North Korea's recent nuclear and missile tests was also raised, with PM Lee reiterating the need to continue to call on Pyongyang to abide by international obligations and commitments.
Yesterday, Asean leaders met among themselves before separate summits with United States President Donald Trump, Chinese Premier Li Keqiang, South Korean President Moon Jae In and Japanese Prime Minister Shinzo Abe.
One key theme was the need for Asean members to stay united on key issues affecting the region.
Mr Trump reiterated his commitment to ensuring "fair trade", as Asean leaders spoke of the importance of warm Asean-US ties.
Leaders of Asean and China announced the start of talks on a code of conduct in the South China Sea, calling for its early conclusion.
"While the situation is calmer now, we cannot take the current progress for granted," Asean leaders said in a statement PM Lee read. Managing the issue well will keep ties on the current positive trajectory, he added. Mr Li said Beijing was committed to be a good neighbour, friend and partner to Asean.
Also raised was the ongoing crisis in which over 600,000 Rohingya have fled Myanmar's Rakhine state for Bangladesh. Mr Duterte's spokesman Harry Roque said two Asean members raised the issue, and Myanmar welcomed offers of humanitarian aid for the displaced.
Security issues will also be raised at the East Asia Summit today.