John Kasich on Thursday denounced GOP presidential rival Donald Trump for predicting that there would be riots if the billionaire fails to secure the presidential nomination at the party’s convention in July.

In a string of Tweets, the Ohio governor called Trump’s language “unacceptable” and an “implicit acceptance of violence.”

Donald Trump said there could be riots if he’s “denied” the GOP nom in a contested convention. That’s more unacceptable language.(1/4) -John

— John Kasich (@JohnKasich) March 17, 2016

This implicit acceptance of violence is the kind of rhetoric that’s pulling people apart. (2/4) -John

— John Kasich (@JohnKasich) March 17, 2016

A true leader urges peaceful debate over violence. Leadership requires responsibility (3/4) -John

— John Kasich (@JohnKasich) March 17, 2016

I have faith the American people want civilized debate over violence. It’s what’s kept our nation the strongest in the world. (4/4) -John

— John Kasich (@JohnKasich) March 17, 2016

{mosads}Critics have charged that Trump is stoking violence at his rallies. Fights have broken out at the events on several occasions, and his supporters and protesters clashed after an appearance in Chicago was canceled.

On Wednesday, Trump further inflamed critics by saying that there would be “riots” at the GOP convention in Cleveland this summer if he comes closest to getting the 1,237 delegates needed to be the nominee, but the nomination goes to someone else.

“I think we’ll win before getting to the convention. And if we’re 20 votes short, or if we’re 100 short, and we’re at 1,100 and somebody else is at 500 or 400 … I don’t think you can say that we don’t get it automatically,” Trump said.

“I think you’d have riots,” he continued.

“I wouldn’t lead it, but I think bad things would happen.”