Donald Trump’s national security adviser said it “obviously” looked as though Joe Biden had won the US election and promised a smooth transition, in the latest acknowledgment of the president’s loss from his allies.

“If the Biden-Harris ticket is determined to be the winner — and obviously things look that way now — we’ll have a very professional transition from the National Security Council,” Robert O’Brien said in remarks at a global security forum, which were filmed last week but aired on Monday.

Mr O’Brien’s promise of a smooth transfer of power comes despite the fact that Mr Trump has not conceded the election. The General Services Administration, which helps manage the functioning of federal agencies, has also not yet recognised Mr Biden’s victory — a pre-requisite for a formal transition to begin.