Madison -- Republicans in the state Assembly began quickly voting on a bill to take away union rights from public workers Friday, without Democrats present.

Democrats charged into the chamber to stop them, but not before Republicans took a key vote.

Assembly Minority Leader Peter Barca (D-Kenosha) called the move an “illegal vote” and has demanded that Republicans rescind the vote.

Republicans had called lawmakers to the floor at 5 p.m., but they began voting minutes before that, when Democrats were not yet on the floor.

As Democrats entered the chamber and screamed to stop proceedings, Republican staff urged leaders to “keep going, keep going.” Republicans took their vote before finally recognizing Barca.

“Unbelievable!” Barca screamed. “Unprecedented! Un-American! Not in keeping with the values of the state. You should be ashamed of yourselves.”

The Assembly is now debating -- loudly, angrily -- how they will proceed.

The vote Republicans took prevents the bill from being amended. It would still need to have two more votes to move it to the Senate.