As ASEAN countries and their citizens look forward to greater prosperity with a more integrated region, they need to keep an eye on two issues, Prime Minister Lee Hsien Loong said.
These concerns are territorial disputes in the South China Sea, where the situation has become more serious in the past year, and the threat of terrorism.
"To thrive, we need a conducive environment for growth in the region," Mr Lee said.
"Recent developments have raised concern in the region," he told fellow leaders yesterday at a closed-door retreat in Langkawi, where he thanked the Philippines and Vietnam for their updates, including on China's reclamation activities.
"If not properly managed, tensions may well escalate and lead to incidents on the ground, or at sea... ASEAN has a role to keep the temperature down," he added.
Mr Lee's comments, released to Singapore media, come amid rising concern in the region over China's reclamation activities in the disputed waters - parts of which four ASEAN member states also lay claim to.
Another worry is the rising activity in the region of militants influenced by the Islamic State in Iraq and Syria (ISIS).
Both issues were also discussed by other ASEAN leaders at the retreat chaired by Malaysian Prime Minister Najib Razak.
The leaders had flown here from Kuala Lumpur, where they discussed their progress towards a more integrated community.
In his remarks, Mr Lee noted that while ASEAN does not take a position on competing claims, it was in the collective interest of the member states to maintain peace and stability as well as freedom of navigation and overflight in the South China Sea.
"All of us want to be friends and to have constructive relations with each other, within ASEAN and with partners in the region, including China," he said.
He called on the involved nations to implement fully the declaration of conduct, an existing agreement between ASEAN and China to manage tensions, and to adhere to international law.
He also said ASEAN should work with China to conclude a Code of Conduct to help avoid incidents in the South China Sea.
Asked by Singapore media on how much urgency there was on this code, he said there was pro- gress, but "to get it done sooner, all the parties have to agree to get it done sooner. And it is not clear that all the parties want to do it as soon as possible".
Mr Lee also dwelt on the threat of terrorism, notably from ISIS. He cited how ISIS propaganda had drawn many from the region to go there and fight and led others to plot acts of terror in their own countries.
This was why countries had to co-operate more closely through security action and intelligence sharing, to apprehend and pre-empt would-be terrorists.
They also had to address radical ideology, and rehabilitate and reintegrate extremists, he added.
ASEAN leaders adopted a Langkawi Declaration on the Global Movement of Moderates, in which they agreed to step up co-operation to amplify moderate voices and drown out extremist ones. They also pledged to boost interfaith dialogue and back efforts to address violent extremism.
This article was first published on April 28, 2015.
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