Markets around the globe had earlier cheered reports of a "Phase 1" trade deal between the United States and China, however a dearth of details around the agreement has curbed enthusiasm.
"The Asia-Pacific Economic Cooperation meeting next month, where Trump and Xi will be meeting, will be a key event to watch out for," Joel Ng, an analyst at KGI Securities said.
"If they don't have a deal, then it is likely that December 15 tariffs come into effect, and that will be really negative for the markets."
The long-drawn Sino-US trade war has largely weighed on Southeast Asian economies, which count China as their top trade partner.
Philippine stocks snapped a three-day winning streak to post its worst session in nearly a week, as weakness in financial and consumer sectors weighed.
Index heavyweight SM Prime Holdings and SM Investments Corp were among the biggest drags on the Manila index, shedding 2.8% and 1.5% each.
Singapore's Straits Times index declined 0.3%, dragged by financials and industrial firms.
Capitaland Mall Trust and Singapore Technologies Engineering lost 1.1% and 1.2%, respectively.
Malaysian stocks edged lower after three consecutive sessions of gains. Mobile communication service provider Digi.com Bhd and IHH Healthcare slipped 1.9% and 2.4% each.
Bucking the trend, Indonesian stocks advanced 0.5%, buoyed by materials and consumer staples firms.
Data released earlier in the day showed that Southeast Asia's largest economy swung back to a trade deficit in September as the pace of the decline in imports was slower than expected.
Pulp and paper products maker PT Indah Kiat Pulp & Paper and tobacco firm PT Japfa Comfeed Indonesia jumped 11.6% and 1.9%, respectively.