CLEVELAND -- Ohio Gov. John Kasich's choice to skip the Republican National Convention in Cleveland is turning into a feud with Donald Trump's campaign.

It started with a comment from Trump campaign chief Paul Manafort, who said Kasich is "embarrassing" Ohio by refusing to attend.

Manafort also to the audience at a Bloomberg breakfast that U.S. Sen. Rob Portman was "upset" with Kasich and believes the governor is hurting his re-election campaign in Ohio.

#RNCinCLE

State GOP Chairman Matt Borges fired back, saying in a tweet that Manafort "doesn't know what he's talking about."

"Manafort still has a lot to learn about Ohio politics," Borges tweeted, adding: "Hope he can do better."

Ohio loves our governor. He turned this state around and united Ohioans. No wonder he has a 60% approval rating. — Matt Borges (@ChairmanBorges) July 18, 2016

Meanwhile, Portman campaign manager Corry Bliss called Manafort's account "totally false." Bliss said Portman and Kasich "are working hand in hand" to defeat Democrat Ted Strickland and said any suggestion otherwise "is inaccurate."

Ohio was Kasich's only win in the GOP presidential primary, and it's a crucial swing state for any Republican hoping to win the White House. Recent polling has Trump deadlocked in the state with presumptive Democratic nominee Hillary Clinton.