Ryan Zinke to step down as Trump administration's Secretary of the Interior

WASHINGTON -- President Donald Trump says Interior Secretary Ryan Zinke (ZIN'-kee), who's facing federal investigations into his travel, political activity and potential conflicts of interest, will leave the administration at year's end.

Trump tweets that Zinke "accomplished much during his tenure" and that a replacement would be announced next week. The Cabinet post requires Senate confirmation.

Zinke, a former Republican congressman from Montana, is leaving weeks before Democrats take control of the House, a shift in power that promised to intensify probes into his conduct.

Zinke played a leading part in Trump's efforts to roll back environmental regulations and promote domestic energy development.

His departure comes amid a staff shake-up as Trump heads into his third year in office. The president on Friday named budget director Mick Mulvaney as chief of staff