Government safety officials in the U.S. are investigating perhaps the hottest electric vehicle on the market right now —  the Tesla Model S.

Three of the vehicles have caught on fire in recent weeks, and a YouTube video of the fires is tarnishing the image of a car that has been the centre of attention since its launch,

Tesla CEO Elon Musk asked the National Highway Traffic Safety Administration to undertake the probe to answer questions the public might have about the safety of electric vehicles as a result of the fires and dispel any fears that the cars may be dangerous.

NHTSA, in documents posted on its website, said it would look into "the potential risks associated with undercarriage strikes" on the Tesla cars. The investigation could lead to a recall, but a decision is likely months away.

Tesla Route Completed

The Tesla Model S has won many fans for its sleek design and reputation for being environmentally friendly. (Eric Risberg/Associated Press)

For the Fremont, Calif.-based car maker and for electric vehicles as a whole, there is a lot at stake.

Tesla might be the most successful electric car in history, with celebrities lining up to buy the first model, the roadster.

Sales of that car helped fund the model S, a sedan version launched in 2012 that was supposed to move the vehicle more into the mainstream. It has sold more than 19,000 models worldwide at a price of $70,000 US to $100,000 US.

Then on Oct. 2, a Tesla travelling at highway speed near Seattle struck a piece of debris on the road, which seemed to have punctured the battery and started a fire.

Fire video went viral

The driver wasn't hurt, as the Tesla's computer told him to pull over and get out.

 But a cellphone video of the accident went viral.

"It's everywhere, which could be expected because it's still a bit of a novelty having electric vehicles, especially one that looks so good and drives so well," automobile journalist Travis Persaud told CBC News.

Since then, there have been two more similar incidents involving Model S sedans. No one has been injured,

Tesla's batteries are mounted beneath the passenger compartment and protected by a quarter-inch-thick metal shield. Experts say that if the batteries are damaged, that can cause arcing and sparks and touch off a fire

Electric cars' image at stake

Musk has hastened to defend the electric car, saying any perception that the Tesla is unsafe could hurt the industry.

"If a false perception about the safety of electric cars is allowed to linger, it will delay the advent of sustainable transport and increase the risk of global climate change," he said.

He pointed to the estimated 190,000 car fires, caused by a variety of factors, in the U.S. every year, saying the Tesla shouldn't be centred out.

Most fires happen in gas-powered cars, which make up the vast majority of cars on U.S. roads.

Tesla's stock rose more than 400 per cent earlier in the year as the Model S won accolades from Consumer Reports and other magazines. But it has fallen 37 per cent since the first fire was reported on Oct. 2 and now trades in the $121 range.

Stock analysts at Barclays have downgraded Tesla stock, saying sales could take a 20 per cent hit because of the probe. 

With files from The Associated Press