WASHINGTON (Reuters) - Donald Trump endured some blunt exchanges when he met Republican members of Congress on Thursday but several lawmakers, including past critics, emerged with encouraging words about their presumptive White House nominee. Republican aides cited good attendance from both houses of Congress at the two closed-door meetings, even though some lawmakers made a point of staying away, citing previous commitments. The New York businessman-turned-politician has sought in speeches and meetings in recent weeks to unite the party behind his unorthodox candidacy and to reassure Republican leaders about his conservative credentials. In a Miami speech on Friday, Trump will say the economic policies of Democrats like President Barack Obama and Hillary Clinton, the party’s presumptive nominee, have harmed minorities, said Steve Moore, a Trump economic policy adviser.   Trump drew 41 of 54 Republican senators to the U.S. Senate meeting where he called out three senators who had been critical of his candidacy, according to Republican aides familiar with the meeting. Trump campaign manager Paul Manafort said the meetings with lawmakers were positive and productive, adding characterizations of discord “attributed to unnamed sources, are wholly inaccurate.”   Trump also met privately with Senator Ted Cruz, his former rival for the Republican nomination. They did not discuss an endorsement but Cruz did accept Trump’s invitation to speak at the Republican National Convention in Cleveland the week of July 18, Cruz spokeswoman Catherine Frazier said. At the first session on Thursday, with members of the House of Representatives, Trump shared a hug with House Speaker Paul Ryan, a Republican who has often criticized Trump even while endorsing him, lawmakers said. They joked a bit about some of their past exchanges during an hour-long session, and Trump took questions. “I’m going to make you proud,” Representative Bill Flores quoted Trump as saying. Trump won grassroots support during months of state-by-state nominating contests for the Nov. 8 election with a pledge to ban Muslims temporarily from entering the United States and to build a wall on the U.S. border with Mexico. He regularly annoys party leaders with inflammatory remarks. Flores, a Texan who heads the Republican Study Committee, the largest conservative grouping in Congress, had criticized Trump, including for having questioned a U.S. judge’s motives because of his Mexican ethnicity. Flores had said he wanted to see “more vision and less trash talk” from the presumptive nominee. After Thursday’s session, Flores said he felt better about Trump. “Based on what I have heard today, I’ve got the confidence that you are going to see a lot more in terms of visionary messaging,” Flores said. “Today was extremely positive,” said New York Republican Peter King, another representative who has criticized Trump. “There was not one negative moment.” But not everyone was won over. “I need to be persuaded,” said Representative Charlie Dent, a moderate Republican from Pennsylvania who said he would not support either Trump or  Clinton. Trump’s session with Republican senators sounded more turbulent. The Washington Post reported details of a combative exchange between Trump and Senator Jeff Flake, an Arizona Republican who has expressed concern that Trump’s comments on immigration will cause Hispanic voters in the state to reject him. When Flake stood up and introduced himself, Trump told him, “You’ve been very critical of me,” the Post said. “Yes, I’m the other senator from Arizona — the one who didn’t get captured — and I want to talk to you about statements like that,” Flake responded, referring to Trump’s past dismissal of Senator John McCain’s record as a prisoner during the Vietnam war. The senator urged Trump to stop attacking Mexicans; Trump predicted that Flake would lose his re-election, at which point Flake informed Trump that Flake was not up for re-election this year. Flake’s spokesman Jason Samuels said the Post account was accurate. Trump also turned to Senator Ben Sasse of Nebraska, who has refused to endorse him, and “said something along the lines of ‘Surely you don’t want Clinton,’” one Republican aide said of the session. Trump said he would win also in Illinois, the home state of a third Republican critic, Senator Mark Kirk, who is in a tight re-election race and recently withdrew his endorsement of Trump. “He’s wrong,” Kirk told reporters several hours later. “I think Trump is going to get a vote like Alan Keyes got, which is about 28 percent,” Kirk said, referring to the Republican who ran unsuccessfully for senator against Obama in Illinois in 2004.   Trump’s Twitter posting as he left Washington showed no sign of discord. “Very interesting day! These are people who love our country!” he tweeted. 