Wenguang Sun, who is critical of China's human rights record, has not been heard from since the Wednesday evening show.
Trump administration seeking to ratchet up pressure for trade concessions by proposing a higher 25-percent tariff on $200 billion worth of Chinese imports.
The annual meeting of the 10-nation bloc opens with security concerns.
US official, who spoke on the condition of anonymity, said Pyongyang gave almost no information to help identify the remains.
Secretary of State Mike Pompeo is heading to Singapore for ASEAN meetings, focused on a free and open Indo-Pacific and regional security.
Yingluck Shinawatra fled the country last August to avoid being jailed over a rice subsidy scheme that ran up losses in the billions of dollars.
The Washington Post cites new satellite photographs.
A top State Department officials says Tehran must be denied any and all paths to weapons of mass destruction.
Philippine legislators this week approved the Bangsamoro Organic Law, which gives money, resources and control to a Muslim region in the south.
The dam collapse follows heavy rains across Southeast Asia, which has led to severe flooding in several parts of Cambodia.