Follow CBSMIAMI.COM: Facebook | Twitter

JANESVILLE, Wis. (CBSMiami/AP) —  House Speaker Paul Ryan endorsed Donald Trump Thursday as Hillary Clinton warned Trump as president would endanger the United States.

READ MORE: COVID In Florida: 4,165 New Cases, 89 Additional Deaths Reported Friday

Ryan’s announcement ends an extraordinary public split between the GOP’s presumptive presidential nominee and the nation’s highest-ranking Republican office holder.

“I had friends wishing I wouldn’t support him. I had friends wishing I would,” Ryan said in an exclusive interview with The Associated Press. “I really didn’t feel any pressure, other than my goal is to make sure that were unified so that we’re at full strength in the fall so we can win the election.”

Related: Trump As President Would Endanger America, Clinton Says

The Wisconsin Republican acknowledged he continues to have concerns Trump’s combative style.

“It is my hope the campaign improves its tone as we go forward and it’s all a campaign we can be proud of,” Ryan said.

Ryan said the endorsement is not the product of any deal with the billionaire developer. Trump won his endorsement, Ryan said, based on “an understanding of our mutually agreed upon principles.” Ryan said he specifically wanted to go over Trump’s approach to executive power, judicial appointments, and his position on abortion.

“Those conversations took some time,” Ryan said.

“I feel much more comfortable that he’s in the same page with us. Most importantly, it is obvious that Hillary Clinton is not,” Ryan said.

Ryan ended a weeks-long standoff with Trump minutes before the interview by outlining his support for the New York billionaire in a column published in his hometown newspaper.

READ MORE: Concern Grows In South Florida As Norwegian Cruise Lines Threatens To Sail Away

Ryan’s announcement marks a significant shift for a GOP desperately trying to come together ahead of a general election matchup against likely Democratic nominee Hillary Clinton. Some of the Republican Party’s best known leaders have vowed not to support Trump, including 2012 Republican presidential nominee Mitt Romney, who tapped Ryan as his running mate.

The day before Ryan’s announcement, Romney signaled support for a possible third-party candidate instead of the presumptive Republican nominee.

Ryan shocked the political world last month by refusing to endorse Trump once the real estate mogul became the last major Republican presidential contender still in the race. The pair spoke privately in a series of Washington meetings last month and their campaigns have maintained contact.

Yet as the GOP’s so-called “Never Trump” movement struggled to identify a viable alternative, many believed it was only a matter of time before Ryan fell in line.

“It was basically getting a comfort level of our idea about where the country is headed and where it ought to go,” Ryan told AP. “It’s more of an understanding of each other and these principles and policies.”

Ryan has embraced reforms to Medicare and Social Security as his signature policy fight on Capitol Hill. Most Republicans in Congress have followed Ryan’s lead to reduce the cost of the popular programs that are contributing to the national debt.

Trump has repeatedly promised not to cut the popular programs, echoing a position more commonly adopted by Democrats.

“It’s no secret that he and I have our differences. I won’t pretend otherwise,” Ryan wrote in a column in the Janesville Gazette. “And when I feel the need to, I’ll continue to speak my mind.”

Ryan’s announcement was released as Democratic front-runner Hillary Clinton was delivering a foreign policy speech excoriating Trump’s approach.

Click here to read more about Campaign 2016.

MORE NEWS: Suspect In Custody After Head-On Collision With FHP Trooper In NW Miami

(TM and © Copyright 2016 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2016 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)