Washington: Michael Flynn's position as US President Donald Trumps national security adviser appeared to be "fluid", after the White House said that the president was "evaluating the situation", the media reported.

Reports have surfaced that the Justice Department warned the Trump administration last month that Flynn misled administration officials regarding his communications with the Russian ambassador to the US, Sergey Kislyak, and was potentially vulnerable to blackmail by the Russians, a person familiar with the matter told CNN.