The Trump campaign asserted on Wednesday that Donald Trump did not backtrack on a pledge to support the GOP presidential nominee if the party did not choose him.

Trump campaign spokesperson Katrina Pierson told CNBC the GOP front-runner is in fact abiding by the terms of his earlier promise, in which he said he would lend his support so long as he felt the party was treating him fairly.

Pierson said Republicans are not treating him fairly.

"You have an entire anti-Trump movement consisting of party elites that are out there trying to stop Trump from winning the nomination, and even joining with Democrats to try to make that happen," she said on "Squawk on the Street."