Fiat Chrysler Group LLC has recalled 1.5 million vehicles in the United States after two hackers came out with an experiment that showed they can control the vehicle after successfully entering its system.

The announcement to recall the vehicles was made on Friday, just a few days after the hackers, Charlie Miller and Chris Valasek, revealed how they were able to control a Jeep Cherokee driven by a news reporter.

According to Insurance Journal, both hackers dove into the vehicle's "telematics system" to give out commands that changed the way the vehicle is being steered and the functionality of the engine and brakes.

The hack was done through a car that was connected to a Sprint network. From the experiment, the hackers discovered that the vulnerability to hacking of the cars lie on the uConnect system installed, reported CNN Money.

The automotive manufacturer has called back the vehicles to upgrade the software currently in place and install a patch that will prevent it from being vulnerable to hackers, noted CDA News.

FCA has already announced that the company will send a USB memory stick to all of its customers so they can upgrade the system the soonest possible time, reported Reuters.

The company has also spoken to its partner telecommunications company to remove access and block all kinds of possible security breach that can be made through the network.

However, the National Highway Traffic Safety Administration (NHTSA) will still make an investigation to see if the patch Fiat Chrysler will put on the system is enough to protect vehicle owners.

The NHTSA and some members of the Congress have previously aired their concerns on the potential security breach of vehicles connected to the Internet.

Two senators have already prepared a bill seeking to make NHTSA the author of standards that can be applied to vehicle manufacturing to prevent the same thing from happening again in the future, added Reuters.

This is not the first time the company has recalled its vehicles. According to the NHTSA, there had been 23 recalls made by FCA. Because of this, the federal government has slapped a fine to the carmaker worth $70 million, wrote Car And Driver.

The penalty also stipulated that the carmaker is required to buy back around 500,000 vehicles because of the recalls.

"Fiat Chrysler's pattern of poor performance put millions of its customers, and the driving public, at risk," said NHTSA Administrator Mark Rosekind. "This action will provide relief to owners of defective vehicles, will help improve recall performance throughout the auto industry, and gives Fiat Chrsyler the opportunity to embrace a proactive safety culture."