Nikki Haley, right, supporting Trump primary candidate Marco Rubio in February | Sean Rayford/Getty Images Trump taps Nikki Haley to be UN ambassador She’s a rising star in the Republican Party and is Trump’s first female appointee to a Cabinet-level post.

President-elect Donald Trump on Wednesday is expected to announce that he has chosen South Carolina Gov. Nikki Haley to be his ambassador to the United Nations, two sources familiar with the decision confirmed.

Haley, 44, a rising star in the Republican Party and a daughter of Indian immigrants, has led South Carolina since 2011. She is Trump’s first female appointee to a Cabinet-level post, and she would be taking on a position that requires intense diplomatic and navigational skills in an often-frustrating international bureaucracy.

In 2015, Haley drew national praise and attention for her response to a mass shooting at an African-American church in Charleston, when she called for the Confederate battle flag to be removed from the grounds of the state capitol. “By removing a symbol that divides us, we can move forward as a state in harmony and we can honor the nine blessed souls who are in heaven,” she said, while acknowledging that some saw the flag as a symbol of tradition.

During the Republican presidential primary, Haley was sharply critical of Trump’s policies, especially his proposal for a temporary ban on Muslims entering the United States, which she called “un-American.” Haley's parents are members of the Sikh faith, but she's a Christian and attends a Methodist church.

Haley endorsed Florida Sen. Marco Rubio ahead of the South Carolina primary, and campaigned with him vigorously throughout the state, which he lost by 10 percentage points to Trump. And when she delivered the Republican response to President Barack Obama’s State of the Union address, Haley urged the party to reject the “angriest voices” — a line widely seen as aimed at Trump.

Trump punched back, tweeting: "The people of South Carolina are embarrassed by Nikki Haley!"

"Bless your heart," she responded.

Haley met with Trump late last week, however, and afterwards described him as “a friend and supporter before he ran for president.”

She explained her criticism of Trump as truth-telling, not an irrevocable breach: “When I see something I am uncomfortable with, I say it. When we met, it was friends who had known each other before.”

Haley has never served in federal government. She also lacks obvious foreign policy experience, and little is known about her stance on contentious topics such as how to end the war in Syria. Like other Republicans, Haley opposed the Iran nuclear deal, which is widely supported by most of the international community.

In 2015, Haley was one of several governors who asked the State Department not to resettle Syrian refugees in their states, citing a “lack of historical and verifiable intelligence” on their identities. Governors lack the power to stop the resettlement, however — and South Carolina today hosts several dozen refugees from Syria.

At the United Nations, Haley will have to deal with the heavy responsibilities involved in America's role as a permanent, veto-wielding member of the Security Council, a role that has in recent years put the United States in frequent opposition to Russia, which holds similar rank.

Under the Obama administration, the U.S. has repeatedly clashed with Russia over how to deal with the conflict in Syria, with the Russians moving to block punitive actions against Syrian President Bashar Assad. But Trump has indicated he wants to find common ground with Russia on Syria and other fronts, and it's possible such clashes may subside during his presidency.

Trump also has signaled he wants to scale back America's overall role in the United Nations, an echo of anti-U.N. sentiment expressed by many Republicans during the George W. Bush presidency. U.N. officials are bracing for disputes with the United States over America's dues to the world body. They also worry that the incoming Trump administration will move to undermine the Paris climate accord, the Iran nuclear deal and other major global agreements in which the U.N. plays a role.

Former U.N. Ambassador Thomas Pickering, who held the role during the George H. W. Bush era, urged Haley to hire professional staff with strong expertise in the United Nations to help her wend her way through the system. Her experience as a governor may be more useful than she realizes, he said in an interview.

"A lot of the work at the U.N. is like working with a state legislature or a national legislature. You’re always counting votes," Pickering said of dealing with U.N. member states. "A lot of the things depend on how you muster the votes for the subject you’re dealing with."

The Washington Post reported early Wednesday and The Post and Courier reportedearlier that Haley’s offer to serve in the post would be announced on Wednesday.

The Post and Courier reported that Haley has taken at least eight trips abroad since taking office in 2011. The paper added that her “chief foreign work centers on negotiating with international companies seeking economic development deals in the state and leading seven overseas trade missions as governor.”

For one of those trips, a 2011 trade mission to Europe, Haley drew fire for costing South Carolina taxpayers $127,000, staying at fancy hotels and attending swanky parties. She lashed out at the Post Courier reporter who wrote a critical story about the trip, calling her a “little girl” (Haley later apologized).

Haley’s husband, Michael, was deployed for nearly a year in Afghanistan with the S.C. National Guard in 2013.

Her nomination would have to be confirmed by the Senate.

Eliana Johnson contributed to this story.