Mike Pence's endorsement of Paul Ryan is a break with Trump

Donald Trump's running mate Mike Pence is breaking with the Republican presidentialnominee by endorsing House Speaker Paul Ryan in his primary fight.

Pence said in a phone interview Wednesday with Fox News Channel that he's pleased to endorse Ryan.

The move comes a day after Trump said in an interview that 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.

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Pence says that he spoke with Trump Wednesday morning about his "support for Paul Ryan and our longtime friendship."

He says Trump, "strongly encouraged me to endorse Paul Ryan in next Tuesday's primary. And I'm pleased to do it."

Meanwhile, Scott Walker's campaign says the Republican governor of Wisconsinwon't join Trump at a Green Bay campaign stop on Friday.

Walker says he'll be visiting northern Wisconsin then, meeting with residents and local officials recovering from flash flooding last month. The campaign says Walker will join Trump at future events if they don't interfere with his work in Wisconsin.

Sen. Ron Johnson, a Wisconsin Republican, also says he won't attend the Trump event, citing a scheduling conflict.

Johnson, who is running for re-election, has criticized Trump's actions in a dispute with the family of slain U.S. Army Capt. Humayun Khan,but continues to support him for president.

Prominent Republicans criticize Trump

Trump's actions and statements are drawing fire from other prominent members of his party.

Republican National Committee chairReince Priebus is among a handful of high-profile Republicans considering whether to confront Trump about his approach to his presidential campaign.

That's according to a Republican official with direct knowledge of Priebus's plans, who spoke on the condition of anonymity to discuss internal party strategy.

Republicans inside and outside of Trump's campaign are brainstorming how to influence the brash billionaire after a series of startling statements, including his refusal to endorseRyan.

Also, aleader of an overseas Republican group says she is growing concerned about Trump.

Jan Halper-Hayes, vice-president of Republicans Overseas, says "there is an element of him that truly is psychologically unbalanced."

Halper-Hayes has previously defended Trump and has said his temperament is suited to high office.

'Donald is out of control right now'

Halper-Hayes, author of Quiet Desperation: The Truth About Successful Men,told the BBC on Wednesday that "Donald is out of control right now and he's not listening to anyone."

But she said that "I think that there is some real concern about his behaviour right now. It's something we need to watch very carefully."

But Trump's campaign chair says the candidate is in control and that reports of brewing anger over his inability to stay on message are overblown.

Paul Manafort says in an interview with Fox News Channel that "the candidate is in control of his campaign."

He adds that "the campaign is in very good shape" and blames Democratic rival Hillary Clinton for suggesting otherwise.

Trumpraises $80 million in July

Trump's campaign says it raised $80 million in July to support his bid as well as the Republican Party.

The numbers mark a significant upswing since May, when Trump was badly outraised byClinton. He now has $37 million cash-on-hand.

Trump is leaning on small donors to finance the bulk of his presidential run.He's also continuing to invest his own money into his campaign, contributing another $2 million last month.

Trump says there's "great unity" in his campaign despite growing dissent and turmoil among his fellow Republicans.

Trump tweeted Wednesday that the campaign unity is "perhaps greater than ever before."