"China, Russia, and Iran may seek to use cyber capabilities to compromise or disrupt critical infrastructure used to support the 2020 elections and may also use influence measures in an attempt to sway the preferences and perceptions of US voters", the report said, adding that white supremacists remain the greatest domestic threat.
DHS warned that Russia can disrupt or damage US critical infrastructure networks via cyber-attacks.
"Russian state-affiliated actors will continue targeting US industry and all levels of government with intrusive cyber espionage to access economic, policy, and national security information to further the Kremlin’s strategic interests", it added.
Moscow can use a range of capabilities including social engineering, publicly known software and hardware vulnerabilities, poorly configured networks, the report noted.
Russia has repeatedly denied the allegations, saying they were invented to excuse the election loss of Democratic presidential nominee Hillary Clinton and to deflect public attention from actual instances of election fraud and corruption.