(CNN) Lawmakers are returning to Congress on Monday following a racist series of tweets from President Donald Trump aimed at four Democratic lawmakers, and Republican leaders as well as rank-and-file members are feeling the pressure to weigh in on the President's comments.

But many leaders in the party are so far not weighing in publicly -- including Senate Majority Leader Mitch McConnell. "If he issues a statement on this we'll be sure to forward," said McConnell spokesman David Popp in response to a question from CNN.

While many Republican leaders in Congress have thus far not spoken out, some GOP members are weighing in publicly to condemn his comments. Here's what some of those Republican senators and representatives have said so far:

Sen. John Cornyn of Texas

"I think what the President said was a mistake and an unforced error and that's about the total of my thoughts," Cornyn told CNN, adding later, "I don't think you are going to change somebody at this point in his life but hopefully he will, like all of us when we make a mistake, he'll learn from it."

Sen. Mitt Romney of Utah

Romney, who was the 2012 Republican nominee for president, told reporters the President "failed badly" with his tweets.

When asked if they were racist, Romney responded, "You know, a lot of people have been using the word and my own view is that what was said, and what was tweeted, was destructive, was demeaning, was dis-unifying, and frankly, was very wrong."

Sen. Roy Blunt of Missouri

Blunt, who is a member of Senate GOP leadership, suggested in a statement that Trump used "unacceptable tactics" similar to the Democrats he wanted to criticize.

"Just because the so-called squad constantly insults and attacks the president isn't a reason to adopt their unacceptable tactics," Blunt said in a statement. "There is plenty to say about how destructive House Democrats' policies would be for our economy, our health care system, and our security. I think that's where the focus should be."

Sen. Tim Scott of South Carolina

Scott, one of two black Republican members serving in Congress, said in a statement that Trump's comments used "racially offensive language."

"Instead of sharing how the Democratic Party's far-left, pro-socialist policies -- not to mention the hateful language some of their members have used towards law enforcement and Jews -- are wrong for the future of our nation, the President interjected with unacceptable personal attacks and racially offensive language," Scott said in his statement. "No matter our political disagreements, aiming for the lowest common denominator will only divide our nation further."

Sen. Susan Collins of Maine

Collins, who's up for reelection next year, said Trump should take down his tweet.

"I disagree strongly with many of the views and comments of some of the far-left members of the House Democratic Caucus -- especially when it comes to their views on socialism, their anti-Semitic rhetoric, and their negative comments about law enforcement -- but the President's tweet that some Members of Congress should go back to the 'places from which they came' was way over the line, and he should take that down."

Sen. Rob Portman of Ohio

Portman said in a statement to CNN, "That's not something I would say, and I think it's divisive, unnecessary and wrong."

During an appearance Tuesday on "New Day," he told CNN's John Berman that "The comments are unnecessary and wrong by their very nature."

"And, you know, I think there's a lot we should talk about and can talk about that unites our country right now," Portman said.

Rep. Will Hurd of Texas

Hurd, the sole black Republican House member, told CNN's Christiane Amanpour that Trump's tweets were "racist."

"I think those tweets are racist, and xenophobic," Hurd said Monday. "They're also inaccurate. The four women he's referring to are actually citizens of the United States. Three of the four were born here. It's also behavior that's unbecoming of the leader of the free world. He should be talking about things that unite, not divide us."

Rep. Pete Olson of Texas

"The Tweet President Trump posted over the weekend about fellow Members of Congress are not reflective of the values of the 1,000,000+ people in Texas 22. We are proud to be the most diverse Congressional district in America," Olson tweeted Monday. "I urge our President immediately disavow his comments."

Rep. Fred Upton of Michigan

"Frankly I'm appalled by the President's tweets," Upton said in a series of tweets Monday. "There's no excuse. Inflammatory rhetoric from both sides of the aisle that is used to divide us just isn't right. It's not helpful."

Sen. Pat Toomey of Pennsylvania

"President Trump was wrong to suggest that four left-wing congresswomen should go back to where they came from," Toomey said in a statement. "Three of the four were born in America and the citizenship of all four is as valid as mine. I couldn't disagree more with these congresswomen's views on immigration, socialism, national security, and virtually every policy issue. But they are entitled to their opinions, however misguided they may be. We should defeat their ideas on the merits, not on the basis of their ancestry."

Rep. Paul Mitchell of Michigan

Mitchell quoted Trump's tweet in his response to the President on Monday.

".@RealDonaldTrump, we must be better than comments like these," he tweeted. "I share the political frustrations with some members of the other party, but these comments are beneath leaders."

Rep. Susan Brooks of Indiana

Brooks, who is retiring from Congress at the end of her term, issued a statement calling Trump's comments "inappropriate."

"The President's remarks to my colleagues across the aisle are inappropriate and do not reflect American values," Brooks said in a statement. "ALL of our elected officials need to raise their level of civility in order to address the serious issues facing our country."

Rep. Peter King of New York

A King spokesman told CNN, "The tweets were inappropriate and wrong."

Rep. John Katko of New York

"The President's tweets were wrong," Katko tweeted. "I have vehemently criticized lawmakers on the far-left when I disagree with the direction they want to take the country — but criticism should focus on policy."

Rep. Mike Turner of Ohio

"I am confident that every Member of Congress is a committed American," he tweeted. "@realDonaldTrump's tweets from this weekend were racist and he should apologize. We must work as a country to rise above hate, not enable it."

Sen. Lisa Murkowski of Alaska

"There is no excuse for the president's spiteful comments -- they were absolutely unacceptable and this needs to stop," Murkowski said in a statement. "We have enough challenges addressing the humanitarian crises both at our borders and around the world. Instead of digging deeper into the mud with personal, vindictive insults --we must demand a higher standard of decorum and decency."

Rep. Elise Stefanik of New York

"While I strongly disagree with the tactics, policies, and rhetoric of the far-left socialist 'Squad,' the President's tweets were inappropriate, denigrating, and wrong. It is unacceptable to to tell legal U.S. citizens to go back to their home country," Stefanik tweeted.

Rep. Tom Cole of Oklahoma

"I am deeply disappointed in the president's comments directed toward fellow Americans and members of Congress," Cole said in a statement. "Use of such language is inappropriate and demeans the office of the presidency."

This story has been updated with additional developments Monday.