Swedish prosecutors withdrew an arrest warrant for the founder of WikiLeaks on Saturday, saying less than a day after the document was issued that it was based on an unfounded accusation of rape.

The rape accusation had been labelled a "dirty trick" by Julian Assange and his group, who are preparing to release a fresh batch of classified U.S. documents related to the war in Afghanistan.

Julian Assange, founder and editor of the WikiLeaks website, talks to reporters in London on July 27. (Max Nash/Associated Press)

The National Prosecutor's Office in Stockholm had issued the warrant late Friday and prosecutors were urging Assange, 39, to turn himself in to police in Stockholm to face questioning in one case involving suspicions of rape and another based on an accusation of molestation.

"I don't think there is reason to suspect that he has committed rape," chief prosecutor Eva Finne said in announcing the withdrawal of the warrant. She did not address the status of the molestation case, a less serious charge that would not lead to an arrest warrant.

A spokeswoman for the Swedish Prosecution Authority later told The Associated Press that the prosecutor hasn't made a decision on that count.

Molestation covers a wide of range of offences under Swedish law, including inappropriate physical contact with another adult, and can result in fines or up to one year in prison.

Earlier, the WikiLeaks Twitter page quoted Assange as saying, "The charges are without basis and their issue at this moment is deeply disturbing."

"We were warned to expect dirty tricks. Now we have the first one," another entry said.

Last month, WikiLeaks published a huge batch of secret U.S. military documents related to the war in Afghanistan. The website has said it's planning to publish another 15,000 such documents in the coming weeks.

U.S. officials have condemned the release of the military and intelligence reports, including those suggesting Pakistan's military spy agency has collaborated with Afghan insurgents.

Assange's whereabouts is unclear. He was in Stockholm last week to lecture on the theme "the first casualty of war is truth."

With files from The Associated Press