AKRON -- Ohio Gov. John Kasich warned that the Republican Party is headed for trouble if it wants to attract young, diverse voters in future years.

Kasich made the comments during an off-the-cuff speech to Michigan delegates Tuesday that touched on everything from recent police killings to his favorite foods in the Wolverine State.

Kasich is not attending the Republican National Convention in his home state this week. Trump was the last Republican to drop out of the race. 

He told delegates that he’s worried about the party’s future, especially its ability to attract young and diverse voters.

“With changing demographics, we can’t keep talking to the same old people,” Kasich said. “There’s not enough of us to talk to. It just won’t work.”

He made a subtle hit at Donald Trump – the Republican Party’s presumptive, nominee who’s had trouble with gaining favor among black and Latino voters – Kasich said the party needs to present a “unified” and “lifting” front.

“It’s going to be the great challenge between Republicans and Democrats,” Kasich said. “The party that can annunciate the hopes, and the dreams and the unity is the party that’s going to do well.”

Kasich has not yet offered his support for Trump.