For a spy agency that likes to blend into the background, the CIA's debut on Twitter has revealed a covert sense of humour.

In a medium heralded for its snide remarks, the Twittersphere gave high praise Friday for the intelligence agency's first tweet, under the handle @CIA: "We can neither confirm nor deny that this is our first tweet."

Within an hour, it had gained more than 67,000 followers.

At first, that raised a question: Was this really the Central Intelligence Agency? Since any number of fake CIA twitter accounts have sprung up over the years, some caution was in order.

The agency quickly confirmed in a news release that it had, in fact, established a presence on both Twitter and Facebook.

Promises 'fun facts,' intelligence history

The CIA got its @CIA handle after filing a complaint with Twitter to wrest control from someone who was using it to impersonate the agency, said CIA spokesman Todd Ebitz.

The agency's tagline: "We are the nation's first line of defence. We accomplish what others cannot accomplish and go where others cannot go."

On both accounts, the CIA promised "photos, reflections on intelligence history and fun facts from the CIA World Factbook."

It also said it would release "updates on CIA career postings and get the latest glimpse into CIA's Museum," which is at the agency's headquarters in suburban Washington and not regularly open to the public.

By Friday afternoon, @CIA was following only 25 Twitter accounts, prompting jokes about how the spy agency actually follows far more people around the world.

"The CIA has followed people for years," tweeted Husain Haqqani, the former Pakistani ambassador to the U.S. "Now tweeple (sic) have a chance to follow @CIA."

Some were not sure it was a good day for social media.

"People say Facebook got lame once your grandmother joined. don't know what to think about @CIA joining Twitter," tweeted electronic privacy activist Parker Higgins (@xor).

A torrent of political commentary followed, such as a mock CIA tweet from journalist Hayes Brown (@HayesBrown): "Remember that time Teddy Roosevelt's grandson helped us launch a coup in Iran?"

Better get used to it, @CIA.