WASHINGTON — The Obama administration acknowledged Thursday that it had attempted, and failed, to build a Twitter-like social media site in Cuba, but insisted that it was part of the Agency for International Development’s effort to encourage political discussions, not a covert program to overthrow the government.

Arguments over the purpose of the program, called ZunZuneo, arose after The Associated Press published a detailed article about it on Thursday, based in part on documents from a contractor for the development agency.

One memo said, “There will be absolutely no mention of United States government involvement.”

The program ran from 2008 to 2012, when it abruptly ended, apparently because a $1.3 million contract to start up a text-messaging system ran out of money. At the time, about 40,000 Cubans were using ZunZuneo, which The A.P. noted was “slang for a Cuban hummingbird’s tweet.”

“No business was able to take this idea and utilize it effectively,” said Matt Herrick, the agency’s spokesman. “So the project ended.”