Donald Trump said Friday he was “really surprised” by House Speaker Paul Ryan declining to endorse him, telling Fox News he has brought “millions” into the party and is getting endorsements “left and right” – except from Ryan.

Despite the presumptive Republican nominee’s claims, he still faces resistance from some senior GOP figures, including Ryan’s 2012 running mate Mitt Romney, a vocal Trump critic who plans to skip the July convention.

But Trump, speaking on “Fox & Friends,” took a shot at the Romney-Ryan ticket, saying the 2012 election was “a race that should have easily been won.” As for Ryan’s reservations about him, the presumptive nominee said he plans to meet with Ryan next week.

“I was very, very surprised [by his comments],” Trump said. “He talks about unity but what is this about unity?” 

Ryan’s office later put out a statement saying he’s invited Trump to meet with House GOP leaders in Washington next Thursday “to begin a discussion about the kind of Republican principles and ideas that can win the support of the American people this November.” The statement said Ryan also will meet separately with Trump, along with Republican Party head Reince Priebus. 

Ryan, speaking earlier on CNN, said Thursday he’s not “ready” at this point to support or endorse Trump. He suggested he wants the billionaire businessman to do more to unify the party first, while leaving himself wiggle room to endorse Trump later on.

Trump swiftly fired back in a statement, saying, "I am not ready to support Speaker Ryan's agenda."

Ryan’s remarks could also cause friction with Trump supporters on Capitol Hill.

Alabama Sen. Jeff Sessions told Fox Business Network Ryan’s stance is a “big mistake.”

Republican National Committee Chairman Priebus told Fox News on Thursday that he thinks “it’s going to work out” in the end.  

"In some cases people are not going to be instantly on board, and I know that can be frustrating for some people. But I think everyone has to ... allow a little bit of the steam to get out and get everybody settled down. And I think this is going to come together."

The Ryan comments, though, underscored the lingering tensions within the GOP over Trump’s presumed primary victory, with some continuing to question his conservative credentials and at times taking issue with his tone.

Speaking with Fox News on Friday, Trump did, however, put to rest speculation that he might look outside the party and choose a Democrat for running mate. Trump said he would not do that.

“We want to have a great ticket. The Democrats have been in there for a long time, the economy is terrible,” Trump said. “I’m going to pick a great Republican, and we’re going to have a tremendous victory.”

Trump was asked about whether he might look outside the party for a VP choice after former 2016 candidate Ben Carson – who is involved in the search process – initially told The Wall Street Journal that Trump could look at Democrats and independents.

A spokesman later clarified that Trump plans to pick a Republican.