WASHINGTON (Reuters) - US President Donald Trump announced on Saturday that his interior minister, Ryan Zinck, would leave office by the end of this year.

"Interior Minister Ryan Zink will leave the administration at the end of the year after serving for almost two years," Trump said, adding that he would announce the appointment of a new minister next week.

Zinck has tarnished his reputation for his costly trips, and judicial authorities have been investigating - according to US media - suspected of misuse of his position.

Zink was appointed interior minister in March 2017 by the Senate.

Since Trump took over at the White House in early 2017, dozens of changes have been made in his administration. Among the most controversial is the dismissal of former Foreign Secretary Rex Tillerson in March on Twitter.

Trump also pushed Justice Minister Jeff Sessions to resign in November after he was sharply criticized for investigating Russian intervention in the presidential election. Justice Department Chief of Staff Matthew Whitaker was appointed acting minister until a new minister was appointed.

Trump announced on December 8 that White House Chief of Staff John Kelly would leave office by the end of this year.

Neky Healy, the US representative to the United Nations, resigned last October and is expected to be replaced by State Department spokeswoman Heather Noyert, according to US media.

In July 2017, White House spokesman Sean Spicer resigned after objecting to Trump's decision to appoint Anthony Scaramuchi as communications director of the Oval Office.