The leaders of Thailand and Cambodia signed an expanded ceasefire deal on Sunday watched over by U.S. President Donald Trump, who landed in Malaysia for a summit of Southeast Asian nations and to oversee a series of pivotal trade talks on the sidelines.

Thai Prime Minister Anutin Charnvirakul and his Cambodian counterpart, Hun Manet, signed the agreement at a ceasefire ceremony in front of a sign that read "Delivering Peace," building on a truce signed three months ago.

"This declaration, if fully implemented, will provide the building blocks for a lasting peace, but more importantly, it will begin the process of mending our ties," Hun Manet said.