Washington: US President Donald Trump's former Russia adviser Fiona Hill has urged Congress' impeachment inquiry not to promote "politically driven falsehoods" casting doubt on Russia's interference in the 2016 US election.

In testimony to the House Intelligence Committee on Thursday (Friday AEDT), Hill said some members of the panel apparently believed Russian security services did not conduct a campaign against the United States during the 2016 presidential race and perhaps Ukraine did.

Some Republican members of the Democratic-led committee, which is leading the impeachment inquiry, have advanced a discredited conspiracy theory, embraced by Trump and promoted by his allies, that Ukraine, not Russia, interfered in the election.

"This is a fictional narrative ... perpetrated and propagated by the Russian security services themselves," said Hill, who until July served as the National Security Council's director for European and Russian affairs.