A hitchhiking robot that captured the hearts of fans all over the world has met its demise after being vandalised in the US.

Canadian researchers who created hitchBOT as a social experiment said someone in Philadelphia damaged the robot beyond repair on Saturday, ending its brief American tour.

The robot was trying to travel cross-country after successfully hitchhiking across Canada last year and parts of Europe.

It set out from Marblehead, Massachusetts, two weeks ago with the goal of reaching San Francisco, but never made it off the East Coast.

The creators were sent an image of the vandalised robot but cannot track its location because the battery is dead.

They do not know who destroyed it or why and co-creator Frauke Zeller says many children who adored the robot are now heartbroken.

The kid-size robot is immobile on its own so gets from place to place by relying on the kindness of strangers.

With its thumb raised skyward, a grin on its digital face and tape wrapped around its cylindrical head that read "San Francisco or bust", it bounced around the Boston area and was briefly taken to sea. One day, it took in a Red Sox game.

The robot was designed to be a talking travel companion and could toss out factoids and carry limited conversation. A GPS within tracked its location and a camera randomly snapped photos about every 20 minutes to document its travels.

During past travels, the robot attended a comic convention and a wedding and had its portrait painted in the Netherlands. It once spent a week with a heavy metal band.