Unintended acceleration in Toyota vehicles may have been a factor in the deaths of 89 people over the past decade, upgrading the number of deaths possibly linked to the massive recalls, the US government said.

The National Highway Traffic Safety Administration said that from 2000 to mid-May, it had received more than 6,200 complaints involving sudden acceleration in Toyota vehicles.

The reports include 89 deaths and 57 injuries over the same period. Previously, 52 deaths had been suspected of being connected to the problem.

Toyota has recalled more than eight million vehicles worldwide since last autumn because of problems with accelerator pedals, floor mats and brakes.

The Japanese car giant paid a record £11.4 million fine for its slow response to an accelerator pedal recall and is facing hundreds of state and government lawsuits.

Toyota said it "sympathises with the individuals and families involved in any accident involving our vehicles".

"We are making an all-out effort to ensure our vehicles are safe and we remain committed to investigating reported incidents of unintended acceleration in our vehicles quickly," it said.

The car maker said "many complaints in the NHTSA database, for any manufacturer, lack sufficient detail that could help identify the cause of an accident. We will continue to work in close partnership with law enforcement agencies and federal regulators with jurisdiction over accident scenes whenever requested".

In the aftermath of the recalls, the US Congress is considering upgrading car safety laws to stiffen potential penalties against manufacturers, give the government more powers to demand a recall and push car companies to meet new safety standards.

Toyota's US sales chief Jim Lentz told Congress last week that dealers had fixed nearly 3.5 million vehicles under the recall and the company and its dealers had conducted 2,000 inspections of vehicles.

He said there was no evidence that electronics were to blame for the sudden acceleration reports.

NHTSA administrator David Strickland told politicians the agency had spoken to nearly 100 vehicle owners who said they had unintended acceleration following a recall fix, but NHTSA had not seen trapped pedals or sticky accelerators in any vehicles that had been properly repaired.

The government is investigating acceleration problems in Toyotas and a separate 15-month study by the National Academy of Sciences will begin in July.

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