WASHINGTON — Donald Trump’s running mate Mike Pence endorsed House Speaker Paul Ryan in his primary fight Wednesday, in Pence’s latest break in position from the billionaire businessman.

Pence said in a phone interview with Fox News Channel that Trump supported his decision to back Ryan as they work to unite the Republican Party.

Trump, Pence said, “strongly encouraged me to endorse Paul Ryan in next Tuesday’s primary and I’m pleased to do it.”

Trump openly taunted the leaders of his own party Tuesday by refusing to endorse Ryan and former Republican presidential nominee John McCain of Arizona in their GOP primaries.

Trump said he’s “just not quite there yet” when it comes to backing Ryan, who has at times been critical of Trump’s most controversial comments. Ryan’s underdog primary challenger Paul Nehlen said Tuesday that Ryan has betrayed Trump in “an act of sabotage against our party.”

So far, McCain, Ryan and other Republicans who’ve reluctantly declared that they plan to back Trump for president appear to be sticking with him.

Trump’s slap at two of the nation’s most prominent Republicans escalated GOP turmoil barely a week after a convention intended to promote party unity.

This is not the first time Pence has broken protocol and expressed an opinion different from that of his running mate. Last week, he issued a statement condemning Russia for any alleged tampering in the U.S. presidential race, after Trump said in a press conference that Russia should locate Democrat Hillary Clinton’s missing emails — a comment Trump later said was meant to be sarcastic.

Pence also defended a military mom’s right to criticize Trump’s controversial comments about the Muslim parents of a slain U.S. Army veteran. Trump later lashed out at the media’s coverage of the controversy.