MADISON, Wis. (AP) -- A Wisconsin judge is set to hear more arguments on whether signatures on recall petitions against nine state senators were gathered improperly.

Six Republican senators and three Democratic senators face recalls over their positions on Gov. Scott Walker's contentious collective bargaining law.

But both sides argue the recall petitions against them are invalid. The Republicans maintain signature gatherers didn't properly submit their initial paperwork. The Democrats contend there was widespread fraud in signature collection against them.

The first round of primaries for the Republicans' challengers is set for Tuesday.

Dane County Circuit Judge Richard Niess is set to hear more arguments from both sides in a consolidated lawsuit Friday morning. He has said he will issue a ruling before Tuesday.