Candidates and dark-money groups that have tried to influence Montana elections since the U.S. Supreme Court's 2010 Citizens United decision will now have disclose more information more often.

New rules that govern a campaign finance law passed last year took effect Friday with their publication by the Montana Secretary of State.

Commissioner of Political Practices Jonathan Motl says the rules add a day for candidates and political committees to file campaign reports before primary and general elections. Disclosure requirements have been extended to issue-advocacy groups that produce advertisements mentioning an election or a candidate.

Candidates and committees also must file their reports electronically.

Motl says the state is obligated to make campaigns more transparent after the Citizens United decision that allowed corporations and unions to spend unlimited money in elections.