Top Republican Eric Cantor endorsed Mitt Romney on Sunday for president of the United States, giving the frontrunner a boost as the primary nomination contest reaches a critical stage.

Cantor's endorsement, the first from a top member of the Republican congressional leadership, was seen as the strongest sign yet that the party establishment wants the increasingly bitter primary battle wrapped up soon.

Romney is the clear frontrunner for the Republican nomination to take on President Barack Obama in November but has faced stubborn challenges from two main rivals, Rick Santorum and Newt Gingrich.

"I cast my vote already in Virginia for Mitt Romney and I'm here today to tell you that I'm endorsing Mitt Romney in his candidacy for the presidency of the United States," Cantor, the House Majority Leader, said on the NBC news program "Meet the Press."

Romney, a former Massachusetts governor and millionaire businessman, is "going to best be able to lead this economy back to a growth mode, create jobs so people can feel better about the future," Cantor said.

"I just think there's one candidate in the race who can do that, and that's Mitt Romney."

His endorsement came just two days before Super Tuesday, a potentially pivotal day in the nominating battle, when 10 states vote at once.

Super Tuesday essentially ended the Republican nomination battle in 2008, when Romney capitulated and Senator John McCain went on to become the nominee.

Cantor's home state of Virginia votes on Tuesday and Romney is the overwhelming favorite there, as both Santorum, a former Pennsylvania senator, and Gingrich, a former House speaker, failed to get on the ballot.

Texas congressman Ron Paul is the fourth candidate left in the race but is not seen as having enough support to be a realistic contender for the nomination.