Toyota intends to aggressively defend itself against lawsuits and “speculation” about its safety credentials in the wake of a series of large recalls, a top US executive has said.

The automaker has not yet decided whether it will challenge a record US$16.4m fine US safety officials announced on Monday, Don Esmond, senior vice president in charge of automotive operations for Toyota Motor Sales USA, told news agency Agence France-Presse (AFP).

The fine was imposed after a Department of Transportation review of 70,000 pages of documents found that Toyota “knowingly hid a dangerous defect for months from US officials and did not take action to protect millions of drivers and their families.”

Safety officials also cautioned that further fines could be imposed when it completes its review of Toyota’s handling of problems related to sudden, unintended acceleration which have been blamed for more than 50 US deaths and resulted in the recall of more than 8m vehicles worldwide.

Toyota is facing at least 97 lawsuits seeking damages for injury or death linked to sudden acceleration and 138 class action lawsuits from angry customers suing to recoup losses in the resale value of Toyota vehicles following the recalls.

Esmond said he had not yet reviewed the Department of Transportation’s findings and was “not sure what they’re basing” the results on.

Asked whether the finding would make Toyota more vulnerable to lawsuits, Esmond said Toyota would aggressively defend itself to ensure it was not held responsible for problems it did not cause.

He noted that driver error was often found to be the cause of sudden, unintended acceleration and that Toyota has set up a “swat team” to quickly investigate any incidents.

“We’re going to be defending ourselves,” he said in an interview following a meeting with dealers in the Chicago area. “I would think the best way to do that is with science.”

AFP noted that Toyota, which was criticised for a bungled and slow initial response to the recall crisis, had become significantly more proactive in recent weeks.

It had hosted a series of media briefings to hit back at claims that there were problems with its electronics and highlight the “inconsistencies” in a highly-publicised account of a runaway Prius.

“Speculation is a lot easier than science,” Esmond said.

“At the end of the day if there’s something wrong (with the electronics) we want to know too. But we thoroughly believe there isn’t.”

Esmond said the Japanese automaker had to be “careful” ahead of the congressional hearings and needed to take responsibility for its mistakes, but now planned to “more aggressively present Toyota’s side of the equation.”

“We stumbled. I don’t think we fell flat on our face,” he said, noting that Toyota’s US sales grew by 40.7% in March while its share of the retail market hit an all-time high of 19.6%.

While tempting incentives helped “kick-start” the sales, Esmond said consumers would not be buying Toyotas if they thought they were unsafe.

“We’re standing by our product and we’re very grateful that the customers stood by us,” he said.