Concerns about escalating geopolitical rivalries dominated weekend meetings between leaders of the Association of Southeast Asian Nations and bigger powers, with Indonesia, the body's new chair, ending the summit with a vow not to let the region become the front line of a new Cold War.

After formally taking over the ASEAN chairmanship, Indonesian President Joko “Jokowi” Widodo said Sunday in Cambodia’s capital of Phnom Penh that the 10-nation bloc must become “a peaceful region and anchor for global stability, consistently uphold international law and not be a proxy (for) any powers.”

ASEAN nations, which have a combined population of about 700 million people, “should not let the current geopolitical dynamic turn into a new Cold War in our region,” Widodo said amid concerns over the rapid deterioration in Sino-U.S. ties, which has led the two powers to vie for influence in the fast-growing region.