Toyota Motor Corp was hit by a planned lawsuit by California prosecutors on Friday over vehicle defects and by renewed political pressure to cooperate with investigators on cases of runaway cars.

A spokeswoman for Orange County District Attorney Tony Rackauckas said he was filing the lawsuit against Toyota's U.S. sales arm -- Toyota Motor Sales USA -- to enjoin them from continuing to endanger the public through the sale of defective vehicles and deceptive business practices.

Toyota had no immediate comment on the lawsuit, which marked the first time that state or federal prosecutors have joined in the growing list of plaintiffs with pending cases against the automaker.

In addition to pending class-action lawsuits, Toyota also faces a probe by the Securities and Exchange Commission and a criminal investigation by federal prosecutors.

The latest legal challenge comes at a crucial time for Toyota, which has been working to win back consumers and demonstrate that it has taken steps to address mistakes the automaker has acknowledged compromised its vehicle quality.

Separately on Friday, Connecticut Attorney General Richard Blumenthal said he was pushing Toyota to investigate a pair of accidents involving Camrys in the state in the past week.

In New York, Sen. Charles Schumer, a Democrat, said he wanted to see the automaker move to probe the cause of an accident in his state involving a Prius with a potentially stuck accelerator pedal.

A string of highly publicized incidents this month involving Toyota vehicles has threatened to overshadow a carefully planned campaign by the automaker to win back car shoppers after it briefly shut down sales of popular models in late January.

In the most prominent example which surfaced on Monday, a San Diego-area man claimed that his Prius surged out of control for some 20 minutes while police dispatched a patrol to help him stop.

Toyota and the National Highway Transportation and Safety Administration are investigating that case, which came just hours after Toyota called a news conference to demonstrate why it believed there was no evidence of a flaw with the electronic systems used to control acceleration in its cars.

TOYOTA SAYS SALES UP

Toyota has recalled more than 8 million vehicles globally to address the risk that accelerator pedals on a range of its vehicles could become stuck because of a loose floor mat or a mechanical glitch in the pedal assembly.

Unintended acceleration in the company's Toyota and Lexus vehicles has been linked to at least five U.S. crash deaths since 2007. Authorities are investigating reports alleging 47 other fatalities over the past decade.

Orange County is just north of San Diego County, where a California Highway Patrol trooper and three members of his family were killed in a crash last August involving a Toyota vehicle.

That crash, which Toyota has said appears to have been caused by a loose floor mat, prompted the first in a series of accelerator-related recalls by Toyota and drew new scrutiny to a rising trend of consumer complaints about unintended acceleration from U.S. safety regulators.

Toyota has its U.S. sales headquarters in nearby Torrance, California.

Toyota executives have been visiting dealers across the United States this week in a bid to focus attention on a campaign of aggressive discounts credited with sending sales sharply higher in March.

Toyota Senior Vice President for U.S. sales, Don Esmond, told Reuters on Friday that the automaker's U.S. sales were up 40 percent from a year earlier through the first 10 days of March.

He said the automaker had not decided whether to extend unprecedented incentives, including rebates and dealer incentives of up to $4,000 and zero-percent financing into April, a move analysts say could stoke sales at the expense of profit margins.

We will continue to keep our dealers competitive, Esmond said.

(Writing by Kevin Krolicki, additional reporting by Soyoung Kim in Detroit, editing by Matthew Lewis)

Toyota California Lawsuit