SAN FRANCISCO - Google is running a secret research lab in the San Francisco Bay Area, where the tech giant invests to experiment and invent what may be world-changing technologies for the future, US media reported on Monday.

According to The New York Times, at the lab dubbed Google X, engineers are working at some 100 projects from robots, smart refrigerators to Internet-enabled dinner plates and a "space elevator", a proposed non-rocket space launch structure.

An unnamed Google engineer familiar with the lab told the newspaper that it was run as mysteriously as the CIA with two officers, a nondescript one for logistics on the company's Mountain View campus and one for robots in a secret location.

Scientists working at the lab include many roboticists and electrical engineers hired from Microsoft, Nokia labs, Stanford, MIT, Carnegie Mellon and New York University. Google's co-founder Sergey Brin is said to be "deeply involved" in Google X.

The lab is reportedly headed by Sebastian Thrun, one of the world's top robotics and artificial intelligence experts. He teaches computer science at Stanford University and invented the world's first self-driving car.

A Google spokeswoman would not confirm the existence of the lab, but said Google likes to invest in speculative projects.

"While the possibilities are incredibly exciting, please do keep in mind that the sums involved are very small by comparison to the investments we make in our core businesses," she told The New York Times.