Republican presidential frontrunner Donald Trump met Monday in Washington with congressional Republicans and other conservative leaders, attempting to forge a relationship with party leaders while urging them to “embrace this movement.”

Trump described the meeting as a success and just the “beginning” of such efforts, as he tries to convince a seemingly reluctant GOP establishment to join forces with him.

“We had a really good meeting. It is a beginning, but it was a very good one, with some of the most respected people in Washington,” Trump said after the private discussion with roughly two-dozen Republicans including Sens. Tom Cotton of Arkansas and Alabama's Jeff Sessions, who has already endorsed Trump.

The billionaire businessman sought the meeting as he adds to his delegate count, vowing he will eventually clinch the nomination. Yet he still faces opposition from rivals Ted Cruz and John Kasich and plotting by some Republicans to derail his outsider campaign with an alternative candidate.

“If people want to be smart, they should embrace this movement,” Trump said. “If they don’t want to be smart, the whole thing could go down.”

Among those also in attendance Monday was New York GOP Rep. Chris Collins, whose post-meeting analysis was similar to Trump’s and who sounded a sense of the inevitable.

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“Mr. Trump will be our nominee. We need to bring the rest of the party to unite us to stop Hillary Clinton,” he told reporters, adding the GOP front-runner’s dialogue with Washington Republicans was “just starting.”

No members of either House or Senate GOP leadership were known to have been in attendance, including Senate Majority Leader Mitch McConnell or House Speaker Paul Ryan.

Trump said Monday that he has had a good conversation with each of them.

McConnell told Fox News on Sunday that he would be home in Kentucky. However, Ryan along with Trump was in Washington on Monday to speak at the annual policy conference for the American Israel Public Affairs Committee, a major pro-Israel group. 

The meeting was also attended by former South Carolina Sen. Jim DeMint, who now runs the influential Heritage Foundation conservative  think tank, as well as former House Speaker Newt Gingrich and wife, Callista.

Among the GOP establishment’s concerns about Trump is that his comments and views about women, Muslims and some Mexican immigrants are too divisive to win the White
House. And more recently, the violence at his campaign events have added to such concerns.  

Trump suggested after the meeting that he understood the establishment’s fears. But he argued that he has the support of millions of everyday Americans and cited as proof that GOP voter turnout is up this year by 72 percent.

“I’m an outsider. I understand,” Trump said. “They are senators, governors, congressmen, women. They are not used to this. … But I have many, many people behind us. And to be honest with you guys, Republicans should embrace me.”

Also attending the meeting at the Jones Day law firm, at the base of Capitol Hill, were GOP Reps. Duncan Hunter Jr., Calif.; Tom Marino, Pa.; Scott DesJarlais, Tenn.; and North Carolina’s Renee Ellmers, the only other woman in the room besides Callista Gingrich.

DesJarlais described the meeting as “very frank” and “honest,” with discussions on such topics as foreign policy, Republicans’ support of Israel, defeating Democratic front-runner Clinton and Trump’s potential Supreme Court nominations. 

Others at the meeting said Trump asked for their support. They said some in attendance already supported Trump while others came to “test the waters.”

Collins said the violence at Trump rallies was only discussed in the context of organized protesters trying to disrupt free speech.

Ellmers, who voted for Trump in the North Carolina GOP primary, told Fox News that Trump’s remarks about women were discussed.

“Women are going to choose the next president, they care very much about all kinds of issues. National security is a main issue, soccer moms of yesterday are security moms of today,” she said. “I know he's made some off-the-cuff comments. I certainly don't condone them, but I know the sense of un-comfortability as a Republican, I think, we need to concentrate on things we agree with, we need to come together in a unified party.”

Fox News' Chad Pergram contributed to this report.