Washington: US President Donald Trump announced that he will nominate Kelly Knight Craft, the country's incumbent Ambassador to Canada and a major Republican donor, to be Washington's Ambassador to the UN.

Craft is set to succeed Nikki Haley, who left the UN post at the end of last year, pending a Senate confirmation. Craft is Trump's second pick after his first candidate, State Department spokeswoman Heather Nauert, withdrew from consideration last week citing family concerns, The Washington Post reported.

Trump praised Craft's tenure at the embassy in Ottawa as "outstanding" as he made the announcement on Twitter on Friday.

"I am pleased to announce that Kelly Knight Craft, our current Ambassador to Canada, is being nominated to be US Ambassador to the UN," Trump said.

"Kelly has done an outstanding job representing our nation and I have no doubt that, under her leadership, our country will be represented at the highest level. Congratulations to Kelly and her entire family."

Trump had announced Nauert as his pick in December, but she was never formally nominated.

According to informed sources, the President considered a number of candidates this week for the prestigious ambassadorship, including Richard Grenell, the ambassador to Germany.

If confirmed, Craft is unlikely to hold the same Cabinet-level rank that Haley had made a condition of taking the job. Without that rank, the next UN Ambassador is not likely to attend as many White House meetings as Haley did and may be less influential.

Secretary of State Mike Pompeo welcomed Craft's selection.

"Ambassador Craft has been an outstanding advocate for America's national security and economic interests in Canada and she is extremely well-qualified to do the same at the UN," Pompeo said in a statement on Friday.

Craft, 56, was a business executive and philanthropist before she was sworn in as Ambassador to Canada in September 2017.

Her husband, Joe Craft, is president and chief executive of coal producer Alliance Resource Partners.

The couple are major Republican donors, having given about $1.5 million to party candidates in 2016, including $270,800 to Trump's campaign committee or his joint fundraising committee with the Republican National Committee.