Michigan State Police say they were forced to use pepper spray and arrest at least four protesters who were opposing right to work legislation at the Michigan Capitol on Thursday.

Michigan State Police Inspector Gene Adamczyk told the Detroit Free Press that a number of protesters tried to rush the state Senate floor.

"When several of the individuals rushed the troopers, they used chemical munitions to disperse the crowd," Adamczyk said. "It would be a lot worse if someone gets hurt and I failed to act."

WILX reported that the Capitol building had been locked and at least four protesters were arrested during the incident. WILX reporter Brian Johnson estimated that there were around 500 protesters in the building.

Video posted by Michigan Senate Democrats showed Republican state Senator Tonya Schuitmaker angrily gaveling the Senate session into recess as the crowd became rowdy.

"Additionally, Republicans have called in countless State Police officers again today to guard their offices and question the public as they enter the Capitol to protest the Republican agenda," the Democrats wrote. "Frankly, if you have to bring in a massive police presence in order to conduct business at the State Capitol, it might be time for Republicans to rethink what they’re doing."

After initially calling the union-busting right to work legislation "too decisive," Republican Gov. Rick Snyder on Thursday said that he would sign the bill if it came to his desk. The measure is expect to pass because Republicans control both the state Senate and state House.

"The goal isn’t to divide Michigan," he said at a press conference. "It is to bring Michigan together."

Snyder said that he now supported the legislation because it was about the "freedom to choose" and "fairness and equity in the workplace."

Democratic lawmakers and unions, however, claimed that the bill would lower wages and reduce benefits for workers.

"Gov. Snyder campaigned on a promise of unity, but instead he’s ushering in an era of divisiveness across Michigan by launching an attack against working families," U.S. Representative Gary Peters said in a statement on Thursday. "By trying to jam this through a lame duck session, Gov. Snyder is trying to prevent voters from seeing how he is dividing Michigan instead of working to ensure the future of our state during this fragile recovery."