DETROIT — Toyota has told dealers it's preparing a plan to repair the brakes on thousands of hybrid Prius cars in the U.S.

In a message sent Friday night to dealers, a Toyota group vice president, Bob Carter, said the company is working on a plan and will disclose more details early next week. More than 100 drivers of 2010 Prius cars have complained that their brakes seemed to fail momentarily when they were driving on bumpy roads. The U.S. government says the problem is suspected in four crashes and two minor injuries.

Public awareness of the problem "has prompted considerable customer concern, speculation, and media attention due to the significance of the Prius image," Carter said in the e-mail. "We want to assure our dealers that we are moving rapidly to provide a solution for your existing customers."

Toyota blames a software glitch and says it has already fixed vehicles in production. But it's still deciding how to handle repairs on 270,000 Priuses that were sold in the U.S. and Japan starting last year. The company could announce a full-fledged safety recall or simply ask owners to bring their vehicles in for repairs, since the brakes aren't failing completely.

The problem isn't related to separate recalls involving millions of Toyotas with defective gas pedals and floor mats that could cause unintended acceleration.