 -- Donald Trump has decided to endorse House Speaker Paul Ryan and Sens. John McCain and Kelly Ayotte -- after initially declining to do so and in the case of McCain, assailing him repeatedly.

Trump broke with his usual form, reading from notes. He expressed his admiration for Ronald Reagan and his "big tent" theory.

“We will have disagreements, but we will disagree as friends and never stop working together toward victory," Trump said. "And very importantly toward real change. So in our shared mission to make America great again, I support and endorse our speaker of the house Paul Ryan."

Trump initially said that he hadn't decided whether or not to endorse Ryan, in an echo of Ryan's initial hesitance to endorse Trump, although he ultimately said he would endorse the real estate mogul.

An aide to Ryan later said that the speaker "appreciates the gesture and is going to continue to focus on earning the endorsement of the voters in Southern Wisconsin."

Trump also threw his support behind McCain, of Arizona, who he took to task for being captured and held as a POW during Vietnam.

"I hold in the highest esteem Senator John McCain for his service to our country in uniform and in public office and I fully support and endorse his reelection Very important. We'll work together," Trump said.

In addition to questioning McCain's military service, he also questioned his commitment to veterans.

In an interview with Fox News earlier this week on Tuesday, Trump said of withholding his endorsement, "I'm only thinking about it, I mean I’ve, you know, never been a big fan of John McCain. And I just hate the way our veterans have been treated by John and other people.”

There was concern among party officials that Trump had widened the rift between his campaign and the Republican agenda with his penchant for going off-message and the highly publicized feud with the parents of slain Army Capt. Humayun Khan.

Ryan, McCain, and Ayotte all publicly condemned Trump’s repeated disparagement of Khizr and Ghazala Khan, declaring their support for Gold Star Families.

But, through this endorsement, Trump, for now, has assuaged any fears that the party would grow further divided, proving to both his party and those Republicans still wary of his campaign that he can steer clear of internal battles and focus wholly on his Democratic rivals.

"We don't win at any level with anything and as a unified party, we will lead our country to unity, as well,” Trump said Friday evening. "Very important. We need the unity. We have to win this election. No, we have to win it."

This is a developing story. Please check back in for updates.