Former Trump adviser Steve Bannon has been arrested and charged with fraud over a fundraising campaign to build a wall on the US-Mexico border.

Mr Bannon and three others defrauded hundreds of thousands of donors in connection with the "We Build the Wall" campaign, which raised $25m, the US Department of Justice (DoJ) said.

Mr Bannon received more than $1m, at least some of which he used to cover personal expenses, it alleged.

In court, he entered a not guilty plea.

Mr Bannon, who has been released on bail, was a key architect of Donald Trump's 2016 presidential election victory. His right-wing anti-immigration ideology fuelled Mr Trump's "America First" campaign.

He was arrested on a 150-foot (45m) yacht called the Lady May in Connecticut by agents from the US Postal Inspection Service, which investigates fraud cases. The yacht is owned by Chinese billionaire Guo Wengui, US media report.

Mr Bannon is the sixth former senior aide to Donald Trump to face criminal charges - after ex-Trump campaign chairman Paul Manafort, veteran political operator Roger Stone, ex-Trump lawyer Michael Cohen, ex-deputy campaign manager Rick Gates and ex-National Security Adviser Michael Flynn.