WASHINGTON (Reuters) - The United States has an "ironclad" commitment to mutual defense among the NATO allies, the White House said on Thursday after Republican presidential nominee Donald Trump raised questions about whether he would defend NATO allies if they were attacked.

White House spokesman Josh Earnest declined to directly address Trump's comments to The New York Times but said potential foes should make no mistake or miscalculation about Washington's readiness to defend its NATO treaty allies.

"The U.S. commitment to that pledge is ironclad," Earnest told a briefing. "The president renewed that commitment just two weeks ago today when he traveled to Warsaw, Poland, to attend the NATO summit."

(Reporting by Jeff Mason; Writing by David Alexander; Editing by Eric Walsh)