WASHINGTON — President Donald Trump notched a victory on Wednesday with Rex Tillerson anointed as his secretary of state, but opposition Democrats girded for battle over other nominations, including his US Supreme Court pick.

The Senate confirmed Tillerson, the former chief executive of oil giant ExxonMobil, by a vote of 56 to 43, before he was sworn in at the White House.

Democrats had argued Tillerson’s lack of government experience and ties to Russia would not serve US diplomatic interests well. But four Democrats ultimately joined all 52 Republicans voting in favour.

With Tillerson sworn in, Trump has another key member of his national security team in place, along with his defence and homeland security secretaries and CIA director.

"This is a man that is respected all over the world before he even begins," Trump said at the White House, thanking Tillerson. "He left a very good job for this, I want to tell you."

But battles loomed on Capitol Hill over other key nominees including education secretary-designate Betsy DeVos, with two Republicans crossing the aisle to oppose her, and Supreme Court pick Neil Gorsuch, who was introduced late on Tuesday at the White House.

"He’ll be approved very quickly," Trump said of Gorsuch, who would fill the seat on the high court left empty since conservative justice Antonin Scalia died in February 2016.

But that confidence belies what looks to be a tough confirmation fight in the Republican-controlled Senate, after Trump’s party refused for much of last year to fill the vacant court seat with Barack Obama’s nominee.

Trump is pushing for Senate Republicans led by Mitch McConnell to prevent a likely Democratic filibuster by using what is known as the "nuclear option."

That procedure would change Senate rules to push Gorsuch through with a simple majority in the 100-seat chamber rather than a supermajority of 60 votes. Republicans hold 52 Senate seats.

"If we end up with that gridlock I would say, ’If you can, Mitch, go nuclear,’" Trump said.

Senate Democratic Minority Leader Chuck Schumer pushed right back.

"The answer should not be to change the rules of the Senate, but to change the nominee to someone who can earn 60 votes," Schumer said.

McConnell has not revealed whether he would seek to invoke the nuclear option.

The acrimonious row over Trump’s ban on travelers from seven Muslim-majority countries has further complicated efforts to get his nominees confirmed.

Democrats have vowed to slow-walk confirmation votes.

Their boycott of votes on two Trump picks was dramatically overturned when leaders of the Senate Finance Committee suspended the panel’s rules and approved the nominees for Treasury -- Steven Mnuchin -- and health – Tom Price -- with no Democrats present.

The provocative move stoked already simmering tensions in Congress.

Democrats also boycotted a committee vote for Scott Pruitt, Trump’s choice to head the Environmental Protection Agency, prompting Republican Senator Jerry Moran to brand it "governing by tantrum."

Democrats were not the only ones expressing concerns.

Two Senate Republicans, Susan Collins and Lisa Murkowski, announced their opposition to DeVos, bringing her nomination to the brink of defeat in what would be an embarrassment for the new president.

DeVos is a wealthy donor who has pushed hard for charter schools but whose positions on public education has drawn criticism.

Despite the DeVos hiccup and Democratic obstruction, Trump’s attorney general pick Jeff Sessions was finally approved by the Senate Judiciary Committee on Wednesday following delays. A final confirmation vote has not yet been set. — AFP