Ryan Zinke has formally stepped down from his position as the US' Secretary of the Interior amid numerous investigations into his behaviour while in office.

Zinke has been succeeded by Deputy Secretary David Bernhardt, a former oil lobbyist who is taking on the role of Acting Secretary. A permanent hire to fill the post, which oversees federal land and waters, has not been named. Zinke announced his resignation last month. He had been Interior Secretary since March 2017.