A former Central Intelligence Agency (CIA) employee Edward Snowden, who reportedly leaked the details of US surveillance programme, has disappeared from a Hong Kong hotel where he was staying, according to BBC.

The BBC reported that Snowden checked out from his hotel on Monday and his whereabouts are unknown, but he is believed to still be in Hong Kong.

A petition posted on the White House website to the Obama administration called for Snowden’s immediate pardon.

The petition said Snowden should immediately be issued a full, free, and absolute pardon for any crimes he has committed or may have committed related to blowing the whistle on secret NSA surveillance programmes.

Recently, Snowden told the Guardian that: "The NSA has built an infrastructure that allows it to intercept almost everything. With this capability, the vast majority of human communications are automatically ingested without targeting."

Snowden said he did not commit any crime and told the news paper that: "We have seen enough criminality on the part of government. It is hypocritical to make this allegation against me. They have narrowed the public sphere of influence."

Recently, it was revealed that the NSA and FBI tapped directly into the systems of major tech firms including Microsoft, Google, Apple, Facebook, Yahoo, Skype, PalTalk, AOL, and YouTube.

US President Barack Obama defended Prism citing security concerns and said American citizens and residents were not targeted in the programme.