PHOENIX -- A federal judge's ruling Tuesday cleared the way for Arizona Democrats to use the Internet to cast ballots in their March 11 presidential primary.

The judge denied a temporary injunction sought by a group trying to block the nation's first binding election for public office using the Internet. The plaintiffs said they would appeal.

The Virginia-based Voting Integrity Project sued the Arizona Democratic Party to stop the online voting, claiming it would discriminate against minorities and the poor.

U.S. District Judge Paul Rosenblatt called the planned voting a turning point in Arizona primaries but he refused to dismiss the lawsuit, saying serious questions as to the so-called digital divide remain.

"It may result in having to set aside the results of this election or conduct a special election if there were to be the ruling of the court," he said.

The Virginia group contends affluent whites would have greater access to computers and the Internet and would dilute the minority vote.

Arizona voters may either fill out traditional paper ballots or use a computer terminal to vote online March 11. They also have the option of casting votes early by logging on to the party's Web site from March 7-10.

The state's Republican primary was held Feb. 22.