Updated

California should ban the use of 15,000 touch-screen voting machines (search) in the November election because the equipment malfunctioned in last month's primary, an advisory panel said Thursday.

The state Voting Systems and Procedures Panel (search) said that the machines made by Diebold Election Systems (search) did not perform well last month and that many voters in San Diego County were turned away.

The panel cited a litany of other problems, including fears that the systems are vulnerable to security breaches.

The decision affects machines only in San Diego, Solano, Kern and San Joaquin counties. If Secretary of State Kevin Shelley (search) goes along with the recommendation, those counties will have to revert to paper ballots.

Machines made by Diebold and other manufacturers in 10 other counties were unaffected by the recommendation.

Mark Radke, Diebold's marketing director, said the company disagrees with the recommendation and plans to outline its objections to Shelley, who has until April 30 to make a decision.

San Joaquin County Registrar of Voters Debbie Hench said she was stunned by the news. The county bought 1,626 Diebold touch-screen machines for $5.7 million.

"I don't understand how they can say they didn't work well. We didn't have a problem in San Joaquin County" during the March election, she said.

Many county voting officials said that voters like the touch-screen machines and that the glitches could be fixed easily.

Diebold Election Systems is an affiliate of Ohio-based Diebold, Inc., a leading ATM maker.