HELENA, Mont. (AP) — Conservative groups have asked a federal judge to toss out Montana campaign-finance laws that prohibit corporations from contributing to political committees.

The groups led by Virginia-based American Tradition Partnership say that barring committee contributions amounts to a restriction on free speech. They compare it to the state ban on corporate spending on political ads that was recently blocked by the U.S. Supreme Court.

The plaintiffs also asked U.S. District Judge Charles Lovell on Wednesday to strike down the state's ban on knowingly false statements in political ads and a law requiring that attack ads disclose the candidate's relevant voting record.

State attorneys urged Lovell to reject the groups' request, saying the laws are needed to keep corruption and fraud out of elections.

Lovell did not make an immediate ruling.