CLEVELAND -- The IRS Friday sent a warning to Ohio pastors who are crossing the line from preaching to politics.

IRS Commissioner Mark Everson came to Cleveland to deliver the warning about the crackdown, reported investigator Ron Regan.

This announcement came just a week after a 5 On Your Investigation into two Ohio groups accused of mixing politics and preaching.

5 On Your Side went inside a meeting of a group called Restoration Ohio, led by a Columbus pastor.

The group insists it doesn't endorse candidates, only educates voters. On this day, it gave an award to Republican gubernatorial candidate Ken Blackwell for his support on banning gay marriage.

Another group comprised of 31 Ohio pastors believes Restoration Ohio is breaking the law, and has asked the IRS to investigate.

"They crossed the line and they're not acting as a church, in my mind. They're acting more like a political organization to elect a single candidate," said the Rev. Eric Williams.

Everson delivered a strong warning about illegal campaigning.

"Are we going to let this cancer spread to our charities and churches? Now is the time to act before it is too late," said Everson.

An IRS report found three out of four churches and other tax-exempt groups suspected of illegal political campaigning nationwide actually did so.

Fifty-five of the groups received warning letters and three were recommended for cuts in tax-exempt status. And while Everson would not mention any Ohio group by name, he did have a message for them.

"There has been a disturbing amount of intervention that we have documented. I am concerned about it, and we will make sure that we address it fairly and firmly and it doesn't grow in the coming cycle," said Everson.