The Trump administration is shifting $271 million (220.7 million pounds) earmarked for disaster aid and cyber security to pay for immigration-related facilities, the US Department of Homeland Security and aleading congressional Democrat said on Tuesday.
Creators of fake accounts on Facebook are making themselves harder to track.
Asean hopes to strike a joint agreement on cyber security with Russia.
Prime Minister Hun Sen will attend the 32nd Asean Summit in Singapore beginning.
The Trump administration removed a Moscow-based cyber security firm from lists of vendors used by government agencies, amid concerns its products could be used by the Kremlin to attack US networks.
Ukraine says that Russian security services were involved in a recent cyber attack on the country.