WikiLeaks founder Julian Assange is wanted in Sweden where he has been accused of rape, a prosecutor has said.
Karin Rosander, director of communications at Sweden's prosecutors' office, said an arrest warrant for the 39-year-old Australian was issued late on Friday.
"Julian Assange is wanted for two different issues, one of them is that he's suspected of rape in Sweden," he told the AFP news agency.
He was unable to say what the other accusation was or whether the search warrant was international.
Assange immediately denied the accusations on the WikiLeaks Twitter page.
"The charges are without basis and their issue at this moment is deeply disturbing," he tweeted.
According to the Swedish newspaper Expressen, Assange is also wanted for assaulting a woman.
WikiLeaks said on Twitter: "We were warned to expect 'dirty tricks.' Now we have the first one."
"Expressen is a tabloid; No one here has been contacted by Swedish police. Needless to say this will prove hugely distracting," it said in another tweet.
Assange was in Sweden last week where he announced that the whistleblower website is to publish in "a couple of weeks" a final batch of 15,000 secret document about US military activities in Iraq and Afghanistan.
Last month WikiLeaks published more than 75,000 classified documents, containing details including unreported civilian deaths and covert operations to kill Taliban leaders.
The White House "strongly condemned" the release of the files, saying it was irresponsible and a threat to national security.
Spokesman Robert Gibbs said the lives of coalition forces and Afghans helping them had been put at risk as a result.
But Assange insisted the information he put into the public domain was accurate and said among the reams of information there appeared to be evidence of war crimes.
"It is up to a court to decide really if something in the end is a crime. That said... there does appear to be evidence of war crimes in this material," he said.
In 2007, WikiLeaks moved its servers from the US to Sweden to take advantage of laws protecting whistleblowers and a culture supportive of online mavericks.
However, Swedish laws allow prosecutors to intervene against publication of material deemed harmful to national security.