Berlin, March 19 (IANS): Mass surveillance of US intelligence agencies has become routine, said American whistleblower Edward Snowden while addressing the CeBIT.

"Extensive monitoring has become routine," said Snowden on Wednesday while taking a video interview at the annual IT trade fair taking place in Germany.

"Thus, the activities of the NSA have become invisible. Even in the White House," he added.

The whistleblower further said that surveillance was not confined to the US.

Citing the GCHQ as example, Snowden said the British intelligence agency "has developed programs to monitor webcams which affects billions of people."

Speaking about possibilities of a return to the US, Snowden, who is currently staying in Russia on a three-year residence permit, said "there is no dictation of terms, if I wanted to go home. It would be the best for the U.S. government, too."

He specifically noted that IT experts were also targets of intelligence agencies because they "have access to systems, infrastructure and private records, calling on people working in this industry to come together to protect communication and improve security."

Glenn Greenwald, who had published leaks that exposed the NSA monitoring program "Prism" on the basis of classified documents from Snowden, also showed up on Wednesday.

The American journalist ruled out a complete release of documents from Snowden, saying the secret papers include too much information about people that are being monitored.

"It would be a violation of their privacy if we release all those informations," he added.