Ryan Zinke, Secretary of the Interior responds to a reporters question during a news conference after touring the fire ravaged town of Paradise, Calif., Nov. 14, 2018.
Ryan Zinke, Secretary of the Interior responds to a reporters question during a news conference after touring the fire ravaged town of Paradise, Calif., Nov. 14, 2018.

U.S. President Donald Trump announced Saturday his scandal-plagued Interior Department secretary, Ryan Zinke, will leave his administration at the end of the year.

Zinke's departure was Trump's second high-level personnel announcement in less than a day and the latest in a series of officials to leave the Trump administration under a cloud of controversy.

"Ryan has accomplished much during his tenure and I want to thank him for his service to our Nation," Trump wrote in a Saturday morning tweet, adding that Zinke's replacement will be announced next week.

Trump's announcement, which did not indicate whether Zinke resigned or was fired, comes as the Justice Department reportedly is considering whether to launch a criminal investigation against him. His personal conduct and executive decisions have raised questions about whether he has used his position for personal gain, triggering at least 15 investigations, several of which cleared him of wrongdoing.

The former Republican congressman from the western state of Montana, who has served as Interior Secretary for almost two years, is leaving just weeks before Democrats take control of the House. The transfer of power to Democrats is likely to result in an escalation of the probes into his conduct.

As head of the Interior Department, which oversees federal land and wildlife, Zinke helped lead the Trump administration's successful roll-back of environmental regulations and promote U.S. energy development, but questions about his conduct dogged him throughout his term.

The Interior Department's internal watchdog investigated Zinke for his involvement in a Montana land agreement backed by David Lesar, chairman of the oil field services company, Halliburton.

The agency's Office of Inspector General has referred the investigation to the Justice Department for potential wrongdoing. Zinke, a former Navy SEAL, has denied any wrongdoing.

Zinke also drew criticism for mixing official business with political campaigning and family travel. The IG's office said in an investigation it released in October that Zinke had staffers explore designating his wife an agency volunteer so that she could travel with him at taxpayers' expense. Some of the taxpayer-funded trips were taken to the U.S. Virgin Islands, an Alaska steakhouse and a Montana ski resort.

House Democratic leader Nancy Pelosi of California
House Democratic leader Nancy Pelosi of California holds a news conference at the Capitol in Washington, Dec. 13, 2018.

Democratic Congresswoman Nancy Pelosi, who will oversee the Zinke probes when she assumes the House Speaker's position next year, left little doubt Saturday the investigations will intensify under her watch.

"Secretary Zinke has been a shameless handmaiden for the special interests. His staggering ethical abuses have delivered a serious and lasting blow to America's public lands, environment, clean air and clean water," Pelosi said in a statement.

Pelosi said citizens are burdened with the Trump administration's "unprecedented corruption, cronyism and incompetence" and declared "The American people have demanded a new dawn of transparency, accountability and openness in government."

"When Democrats take the gavel in January," Peloso said, "we will clean up corruption to make Washington work For The People."

Zinke's departure deals a serious blow to a political career over the past decade that began in the state senate and led to a coveted cabinet position.

Zinke is the most recent in a series of officials to depart the Trump administration under controversial circumstances. Friday evening, just hours before Trump announced Zinke's departure, Trump named Office of Management and Budget Director Mick Mulvaney to replace retired Marine General John Kelly as White House Chief of Staff.

Trump Picks Mulvaney as Acting Chief of Staff  

Kelly, like his predecessor Reince Priebus, found the position frustrating. Their authority was repeatedly undercut by the president and other top administration officials, especially presidential daughter Ivanka Trump and her husband, Jared Kushner, both of whom hold senior positions in the West Wing.

White House senior adviser Jared Kushner listens a
FILE - White House senior adviser Jared Kushner listens as U.S. President Donald Trump speaks at a dinner to honor evangelical leadership in the State Dining Room at the White House in Washington, Aug. 27, 2018.

Environmental Protection Agency Administrator Scott Pruitt, the architect of the Trump administration's aggressive campaign to rewrite federal environmental regulations, resigned in July amid numerous ethics investigations into his activities.

Pruitt was not able to overcome allegations of excessive spending and unusually close relationships with lobbyists. Pruitt also was denounced for getting staff members to seek special favors for him and his family, including contacting Chick-fil-A CEO Dan Cathy to help Pruitt's wife open a franchise of the restaurant.

Health and Human Services Secretary Tom Price was forced out in September 2017 after federal investigators said he wasted at least $341,000 by charging taxpayers for his extravagant use of chartered jets and military aircraft.

Other high-profile departures include former Secretary of State Rex Tillerson and former Attorney General and U.S. Senator Jeff Sessions, both of whom were fired by the president.