HARRISBURG — Pennsylvania's Republican Party sued the state's top election official and the community activist group ACORN, accusing the group of fostering voter registration fraud and asserting that the election system lacks adequate safeguards to stop it.

The lawsuit filed Friday asks the state Commonwealth Court to order ACORN to provide lists identifying all the voters it registered and to finance public-service announcements to remind first-time voters that they must present identification at the polls.

"The stakes in this action are enormously high: Unless this court acts quickly and decisively, the right to Pennsylvania's 21 electoral votes may be determined by illegal ballots," the lawsuit said.

ACORN, whose mission is to help low-income citizens organize politically, claims to have registered about 1.3 million voters nationally this year.