Fugitive U.S. intelligence contractor Edward Snowden has opened an account on the social network website Twitter, BBC News reports.

His opening tweet was: "Can you hear me now?"

In his profile, Snowden says he "used to work for the government. Now I work for the public". He quickly gathered thousands of followers.

So far, Snowden, who is wanted in the US for leaking secrets, only follows one other Twitter user - the U.S. National Security Agency (NSA). He is believed to be living in Moscow where he is sheltering from U.S. prosecutors.

In his second tweet - a reply to U.S. astrophysicist Neil deGrasse Tyson - Mr Snowden joked: "Now we've got water on Mars! Do you think they check passports at the border? Asking for a friend."

And in another tweet he said: "Hero, traitor - I'm just a citizen with a voice."

Snowden left the U.S. in 2013 after leaking to the media details of extensive internet and phone surveillance by U.S. intelligence.

His information made global headlines when the Guardian newspaper reported that the NSA was collecting the telephone records of tens of millions of Americans.

Snowden is believed to have downloaded 1.7 million secret documents before he left the U.S.

Although some consider him a traitor for his revelations, many others around the world say he is a champion of civil liberties.

Earlier this year, speaking via video-link to a Geneva audience, he said he would like to be granted asylum in Switzerland.