Workers were seen assembling domed arches and a staging area on the South Lawn in preparation for next month's event.

Workers were seen assembling domed arches and a staging area, which based on online renderings, will form an octagon-shaped ring surrounded by a wire-mesh fence and thousands of temporary seats.

US President Donald Trump previously said the project will be the “biggest event” the UFC has ever had, featuring an “arena right outside the front door of the White House”.

Dubbed UFC Freedom 250, the event is due to take place on 14 June, with the UFC set to spend around $60m (£44.3m) on the project.