PITTSBURGH—Pittsburgh City Councilman Bill Peduto says two top Democrat challengers in the mayoral primary are violating the city's campaign finance law, which caps donations at $2,000 per person and $4,000 per political action committee.

Peduto has filed for an Allegheny County court injunction Thursday saying city Controller Michael Lamb wrongly loaned his mayoral campaign $50,000. And he says Jack Wagner's stated plan to jump start his campaign with $300,000 in leftover money from his war chest as state Auditor General is illegal, too.

Lamb and Wagner both released statements calling Peduto's legal challenge a baseless political "stunt."

But Peduto claims Wagner, in particular, is trying to circumvent the city law by moving donations into his state row office account that far exceeded city campaign limits shortly before Wagner announced he was running for mayor.