Mr Bannon, who wants a less interventionist US foreign policy, told LBC's Andrew Marr that NATO, which was set up after the Second World War to provide security against the Soviet Union, had become "an American security guarantee" for Europe.

NATO member states are meant to put 2% of their GDP into their annual military budgets. But just seven of 30 NATO member states in 2022, the latest figures available - despite Russia invading Ukraine, a NATO neighbour in February that year.

The seven who contributed 2% or more were the US, UK, Greece, Poland and the three Baltic states. Eight members met the required military spending rate the year before.

Mr Bannon, a controversial figure for his right-wing views, denied that Mr Trump wanted to "cut ties" with NATO if he regained the US presidency in November.
 
Mr Trump got his re-election campaign off to a strong start on Monday by winning the Iowa caucus of Republican candidates for the party's nomination.