Toyota Motor Corp on Thursday launched a major new recall of its vehicles on safety concerns related to a defect affecting 2.3 million of its vehicles, including recent models of its popular Camry and Corolla sedans.

The recall comes in the wake of several reports of a mechanical problem involving sticking gas pedals that cause vehicles to accelerate unintentionally.

Most of the vehicles targeted by the new recall were also included in a separate recall of 4.3 million vehicles late last year involving floor mats that could jam the accelerator pedal.

With the latest recall, the carmaker has for the first time, acknowledged that a mechanical problem could cause the vehicles to accelerate out of control.

According to safety experts who have researched motorists' claims, Toyota has in the past, blamed floor mats for the problem.

According to reports in The Times, at least 19 people have been killed in the US, in accidents involving runaway Toyota and Lexus vehicles. This figure is higher than that for all other manufacturers combined. The Times also reports that the acceleration problem in Toyota and Lexus vehicles increased significantly with the automaker installing electronic throttle controls.

Meanwhile, according to Toyota executives, the defective component in the system may be the pedal mechanism itself. Earlier it was thought that the evidence indicated a possible malfunction in the electronic controls, also known as ''drive-by-wire'' systems.

In launching Thursday's recall, Toyota executives said the culprit appeared to be the pedal mechanism itself.

According to Toyota spokesman Bryan Lyons, the company had not found any problem with the electronic throttle that was earlier seen as the culprit.

The issue first came to public notice after a crash involving a Lexus ES 350 near San Diego in August 2009 that claimed four lives. Toyota's president Akio Toyoda offered an apology following the accident.

The accident resulted in the recall of 4.3-million-vehicles, Toyota's largest ever. In a first for the Japanese automaker, Toyota led all automakers in the total number of vehicles recalled in the U.S. last year.

According to Toyota, the latest recall was triggered by reports from motorists who complained of accelerator pedals remaining depressed after they took their foot off the gas.

Toyota said in a statement, "The condition is rare but can occur when the pedal mechanism becomes worn and, in certain conditions, the accelerator pedal may become harder to depress, slower to return or, in the worst case, stuck in a partially depressed position. Toyota is working quickly to prepare the correction remedy."

Toyota has not yet decided a course of action on how it will fix the sticking-pedal problem, but has advised drivers who face the issue to bring the car to a halt with ''firm and steady application of the brakes'' and to notify a Toyota dealer immediately.

The automaker claims in its letter to the National Highway Traffic Safety Administration on Thursday, the problem first came to its notice about in March 2007 and at the time involved its Tundra truck.

The letter said that starting last October, it began receiving more complaints of sticking pedals in the US and Canada. The carmaker attributed the problem to condensation forming on a friction surface under certain circumstances.

The letter also identified CTS Corp as the producer of the suspect pedal assembly.

However, Vinod M Khilnani chief executive of the Indiana-based firm told the Los Angeles Times though he was aware of several Toyota recalls but not know any details beyond that.

Meanwhile, according to safety experts, since last fall, when Toyota said it had solved the acceleration problem with proposed changes to gas pedals, more than 60 new cases of runaway Toyotas had been reported. They believe, the latest recall may still not fix a problem that continues to be linked with serious accidents and deaths.