Swedish prosecutors defended their handling of a rape allegation against the founder of WikiLeaks, saying on Sunday that they had made no mistakes in issuing an arrest warrant and withdrawing it less than a day later.

WikiLeaks founder Julian Assange said the short-lived warrant had damaged his group nonetheless.

The Swedish Prosecution Authority said an “on-call” prosecutor issued an arrest warrant for Mr. Assange late Friday only to see it revoked the next day by a higher-ranked prosecutor, who found no grounds to suspect him of rape.

“The prosecutor who took over the case yesterday had more information, and that is why she made a different assessment than the on-call prosecutor,” said Karin Rosander, a spokeswoman for the authority.

She declined to specify what the new material was, but said there was “absolutely nothing” that suggested errors had been made by either prosecutor.

Mr. Assange was in Sweden last week seeking legal protection for the Webiste, which angered the Obama administration by publishing thousands of leaked documents about U.S. military activities in Iraq and Afghanistan.

WikiLeaks is preparing to release of a fresh batch of classified U.S. documents from the Afghan war, despite warnings from the Pentagon that they could endanger American soldiers and their Afghan helpers.

The secretive Australian remains under suspicion of a lesser crime of molestation, which would not lead to an arrest warrant. Molestation covers a wide of range of offenses under Swedish law, including inappropriate physical contact with another adult, and can result in fines or up to one year in prison.

Mr. Assange called the allegations “without basis” in a Twitter posting and questioned the motives behind them in an interview with a Swedish newspaper.

The tabloid Aftonbladet quoted Mr. Assange as saying the allegations had caused damage even though the rape suspicion was dropped, because WikiLeaks’ “enemies” could use them to discredit the site.

“I don’t know who’s behind this but we have been warned that for example the Pentagon plans to use dirty tricks to spoil things for us,” he said in comments translated to Swedish.