Sen. Mark Kirk (R-Ill.) on Thursday hit back at Donald Trump after the presumptive Republican nominee reportedly said he would lose his reelection bid.

“I guess the bully side of him,” Kirk said when asked by The Associated Press why Trump characterized him as loser during a meeting with Senate Republicans.

{mosads}“We haven’t seen a personality like his too much in the Midwest,” Kirk added. “[He’s a] Eastern, privileged, wealthy bully. Our bullies are made of better stuff in Illinois. We’re much more practical and polite.”

Kirk is considered one of the most vulnerable senators up for reelection this year, but said he’s faced difficult races before.

“I’ve run for election six times in Illinois. Really tough races for the Congress and for the Senate and won every race. Otherwise I wouldn’t be here.”

Trump earlier Thursday had an at-times tense meeting with the Senate GOP caucus in Washington, D.C. Reports emerged that Trump characterized Kirk as a loser for withdrawing his endorsement of the billionaire last month.

Kirk said he could no longer back Trump after the businessman attacked the Hispanic heritage of a judge overseeing a lawsuit against Trump University.

“While I oppose the Democratic nominee, Donald Trump’s latest statements, in context with past attacks on Hispanics, women and the disabled like me, make it certain I cannot and will not support my party’s nominee for president regardless of the political impact on my candidacy or the Republican Party,” Kirk said in a statement on June 7.

“After much consideration, I have concluded that Donald Trump has not demonstrated the temperament necessary to assume the greatest office in the world,” added Kirk, widely considered one of the GOP’s most vulnerable senators.

Kirk, who will face Rep. Tammy Duckworth (D-Ill.) this fall, had previously pledged to support the ultimate Republican nominee.