Donald Trump on Steve Bannon arrest: 'It's very sad'
The US president commented on his former adviser being arrested on fraud charges.
Steve Bannon and three others have been accused of defrauding hundreds of thousands of donors in connection with the "We Build the Wall" fundraising campaign.
The group raised $25m (£19m) for the project, which was to build a wall on the US-Mexico border.
Mr Bannon received more than $1m, at least some of which he used to cover personal expenses, the Department of Justice said.