Washington, Feb 10 : As the FBI is analysing recovered parts of the suspected Chinese spy balloon which was shot down on February 4, it was revealed that the device "was capable of conducting signals intelligence collection operations" and was part of a fleet that had flown over "more than 40 countries across five continents", a US State Department official said.

"We know the PRC (People's Republic of China) used these balloons for surveillance. High-resolution imagery from U-2 flybys revealed that the high-altitude balloon was capable of conducting signals intelligence collection operations," CNN quoted the official as saying on Thursday

Signals intelligence refers to information that is gathered by electronic means -- things like communications and radars.

Senior FBI officials confirmed on Thursday that they have started initial stages of evaluating the pieces of the balloon that were recovered and brought to the Bureau's lab in Quantico, Virginia, on Sunday.