In an interview on ABC’s “This Week” with George Stephanopolous, Donald Trump attacked Ted Cruz’s likability.

“He’s a nasty guy. Nobody likes him,” Trump said in the interview. “Nobody in Congress likes him, nobody likes him anywhere once they get to know him.” This is just the latest installment in a heated rivalry between the two Republican candidates.

Trump questioned Cruz’s eligibility to run for president, since the Texas senator was born in Canada. The issue was raised during the last Republican debate, after a lawsuit claimed Cruz didn’t meet the constitutional requirement limiting the presidency to “natural-born” citizens. The New York Times reports that the suit, filed by 85-year-old trial lawyer Newton Schwartz Sr., wants the Supreme Court to concretely define the phrase.

Trump, who has previously said that Cruz is eligible because his mother is American, told Stephanopoulous that he’d considered filing a lawsuit himself, saying, “I’d like to talk to Ted about it, see how he’d feel about it. ‘Cause you know, when I file suits, I file real suits.”

As for Cruz’s competence as a leader, Trump said, “He’s got an edge that’s not good. You can’t make deals with people like that.” Trump himself has lost numerous deals as a result of his edgy campaign.

Trump’s Twitter feed underscores his focus on beating back Cruz’s campaign. In a rant on the social media site, he described his fellow Republican as a dishonest hypocrite and invoked 9/11 to turn Cruz’s attack about Trump’s “New York values” back on him.