President-elect Donald Trump has appointed House Republican Conference chairwoman and longtime ally Elise Stefanik of New York as ambassador to the United Nations.

Stefanik is Trump’s first Cabinet pick for his second term in the White House.

“I am honored to nominate President Elise Stefanik to serve in my Cabinet as U.S. Ambassador to the United Nations. Elise is an incredibly strong, tough and smart America First fighter,” Trump said in a statement on Monday.

Stefanik said she was “truly honored” by Trump’s announcement.

“I stand ready to advance President Donald J. Trump’s restoration of America First peace through strong leadership on the world stage on day one at the United Nations,” she said in a statement.

News of Trump’s choice was first reported by CNN.

Stefanik, 40, has been a staunch defender of Israel in its response to Hamas’s Oct. 7 attacks and has spoken out about anti-Semitism on college campuses over the past year. A day before last week’s elections, Stefanik reiterated her call for a halt to funding for the United Nations Relief and Works Agency for Palestine Refugees in the Near East, claiming it has been infiltrated by Hamas.

Israel has accused organization staffers of taking part in the October 7 terror attacks, prompting the organization to fire at least 10 people. The Israeli parliament voted in late October to ban the organization’s activities.

Stefanik has served as chairman of the House Republican Conference since May 2021, after then-Rep. Liz Cheney, R-Wyo., was impeached for her vocal criticism of Trump. Stefanik has been a member of the House of Representatives since 2015 and represents New York’s 21st Congressional District, which spans New York State, bordering Vermont and Canada.

Any appointments by Trump that lead to vacancies in the House of Representatives could be problematic for Republicans in the House of Representatives. Although they were able to retain control of the House of Representatives, an election outcome that NBC News has not yet announced, their margin will be slim, and they struggled throughout the previous Congress to maintain effective control of the body with few votes to spare.