Updated: 5:15 p.m.
Four GOP senators joined a growing list of Republicans calling out Donald Trump for his recent remarks that a judge involved in one of his lawsuits could not be impartial because of his ethnicity.
Trump, the presumptive GOP presidential nominee , said the federal judge overseeing a lawsuit relating to Trump University should recuse himself from the case because he is of Mexican descent. Judge Gonzalo Curiel , who was born in Indiana, is the son of Mexican immigrants.
"Donald Trump’s comments on the ethnic heritage and religion of judges are absolutely unacceptable," Sen. Susan Collins said in a statement Monday. " His statement that Judge Curiel could not rule fairly because of his Mexican heritage does not represent our American values."
Florida Sen. Marco Rubio, the son of Cuban immigrants, also criticized the remarks in a television interview. "Quite frankly, I'm very disturbed by the way he's talking about this judge. He's an American."
Texas Sen. Ted Cruz, another Republican of Cuban descent, said, "Of course, it is inappropriate to be attacking a federal judge's race or ethnicity."
On Sunday, Trump also said it is "possible"that a Muslim judge would also be biased against him, during an interview on ABC's "This Week." Trump has called for a temporary ban on Muslims entering the United States.
"Mr. Trump's comments demonstrate both a lack of respect for the judicial system and the principle of separation of powers,” Collins said. Sen. Kelly Ayotte, R-N.H., on Sunday called Trump's remarks are “offensive and wrong, and he should retract them.” She has said she plans to support the GOP nominee but has no endorsed Trump.
Sen. Ben Sasse, R-Neb., took his criticism of Trump's comments a step further, calling them racist.
"Public Service Announcement: Saying someone can't do a specific job because of his or her race is the literal definition of 'racism,'" Sasse tweeted Monday afternoon.
Public Service Announcement: Saying someone can't do a specific job because of his or her race is the literal definition of "racism."— Ben Sasse (@BenSasse) June 6, 2016
Sasse has been one of the leading lawmakers who has been critical of Trump. He wrote in a lengthy Facebook post at the end of February that he would not vote for Trump. Instead, he would look for a third candidate, or a "conservative option," to support in November.
Collins has not endorsed Trump, but said in early May that she will support the party's nominee, according to the Portland Press Herald .
The GOP senator has cultivated a reputation as a Senate deal-maker, willing to buck her party's leadership on occasion. She is one of two Republican senators who has called for the Senate to vote on President Barack Obama's Supreme Court nominee, Judge Merrick Garland.
At a rally in San Diego last month, Trump called Curiel a "hater" who is biased against him. He later told The Wall Street Journal that the judge cannot rule fairly due to his heritage and the Manhattan billionaire's stance on immigration, drawing criticism from House Speaker Paul D. Ryan. The Wisconsin Republican said the statements were "out of left field."
Senate Majority Leader Mitch McConnell of Kentucky said on NBC's "Meet the Press" Sunday that he "couldn't disagree more" with Trump's statements. But he declined to characterize the statements as racist.
McConnell's interview prompted Senate Minority Leader Harry Reid's spokeswoman Kirsten Orthman to issue a statement in response, saying, "Sen. McConnell’s evasions are exactly the kind of moral cowardice that led to Donald Trump’s rise."
Even staunch Trump supporters criticized his remarks. "This is one of the worst mistakes Trump has made," said former House speaker Newt Gingrich, who is said to be on the short list for Trump's vice president. "This man was born in Indiana. He's an American. Period."
Rep. Chris Collins, R-NY, the first member of Congress to endorse Trump, told CNN that Trump's comments were motivated by what the businessman considers biased treatment from the judge. "I don't view themin a racist context, because I don't believe Donald Trump is racist," he said. "He is a frustrated business guy."