Offers $20,000 reward for “information leading to the arrest or exposure of any Obama admin agent destroying significant records”.

WikiLeaks appealed on Tuesday for leaked White House documents before US President Barack Obama leaves office, as its founder Julian Assange again denied that Russia was the source of hacked Democratic party emails that hurt Hillary Clinton’s bid for the presidency.

“System admins: Don’t let the White House destroy US history again! Copy now, then send to WikiLeaks at your leisure,” the secret-spilling website announced on Twitter, shortly before Mr. Assange gave an in-depth interview to U.S. network ''Fox''.

“We are issuing a US$20,000 reward for information leading to the arrest or exposure of any Obama admin agent destroying significant records,” the tweet said.

Mr. Assange gave the interview at the Ecuadoran embassy in London where he sought refuge in June 2012 to escape extradition to Sweden for questioning about an alleged rape.

He shed no light on who provided Wikileaks with thousands of hacked emails from the Democratic National Committee (DNC) and from Clinton campaign chief John Podesta.

WikeLeaks released the documents during the U.S. election campaign in what U.S. intelligence reportedly concluded was an attempt by Russia to tip the election in favour of Ms. Clinton's Republican rival, Donald Trump, who went on to win the White House.

Mr. Assange insisted, however, that no Russian government linked party was the source of the hacked material.

“The source is not the Russian government. It is not state parties,” the 45-year-old Australian said.

Pressed as to whether he thought the leaks of the Mr. Podesta and DNC emails led to Mr. Trump’s election in November, he said: “Who knows, it’s impossible to tell.”

“But if it did, the accusation is that the true statements of Hillary Clinton and her campaign manager, John Podesta, and the DNC head Debbie Wasserman Schultz, their true statements is what changed the election.”

He said his organisation was not political in nature but aimed at providing facts governments do not.

“We have a perfect record, authenticating the information we publish,” Mr. Assange said. “We try to preserve that reputation. What else do we have a record for?”

Mr. Assange is wanted for questioning in Sweden into allegations by a woman who accused him of rape during a 2010 visit to Stockholm.

He has denied the allegation, insisting they had consensual sex.

He has refused to travel to Sweden for questioning, fearing he would be extradited to the US over WikiLeaks’ release of 500,000 secret military files on the wars in Afghanistan and Iraq in 2010.