Australian intelligence services had warned WikiLeaks of "dirty tricks" before Swedish authorities issued a short-lived arrest warrant for founder Julian Assange over a rape claim, he said today.

"We were warned on the 11th (of August) by Australian intelligence that we should expect this sort of thing," Assange said in a telephone interview with broadcaster Al-Jazeera from a secret location in Sweden.

Assange -- whose whistleblowing website is embroiled in a row with the Pentagon over the release of thousands of secret US documents on the Afghan war -- faced allegations from two women in Sweden of rape and molestation.

Prosecutors issued a warrant for his arrest on Friday night on the rape claim but abruptly withdrew it the following day saying that new information had come to light.

"We were warned about dirty tricks and specifically that they would be of a type like this," the 39-year-old Australian said.

Swedish authorities are still investigating the claim of molestation, but Assange insisted that all the allegations against him were untrue.

"It is clearly a smear campaign ... the (rape) accusation was withdrawn six hours later. The only question is who was involved," he said in the interview which was posted on Al-Jazeera's website.

But while Assange had said at the weekend that he believed the Pentagon could be behind the claims, he was more circumspect today, acknowledging that he could not say for sure.

"We don't have direct evidence that this is coming from a US or other intelligence" agency, he said. "We can have some suspicions about who will benefit, but without direct evidence I won't be making direct allegations."

The Pentagon said yesterday any allegation of dirty tricks was "absurd".

Assange has promised to publish 15,000 new documents about the war in Afghanistan, after posting 77,000 leaked documents online late last month in a move that the Pentagon said could endanger the lives of informants.

He told Al-Jazeera the new release would take place in "two to four weeks.