The upgrade will be compatible in all Tesla cars made in the past two years, Musk said in a series of tweets http://bit.ly/2Puaeur on Thursday.

"Car will drive to your phone location & follow you like a pet if you hold down summon button on Tesla app", Musk said in one of his tweets, without giving details.

The upgrade will enable owners to operate their vehicles remotely like a big remote controlled car as long as it falls within the line of sight, Musk also said.

Summon, part of Tesla's driver-assist Self-Pilot system, currently allows Model S drivers to park their cars from outside the vehicle in tight spots or to move the cars short distances to shift parking spot.

(Reporting by Philip George in Bengaluru; editing by Patrick Graham)