In an online interview with Time magazine, Assange on Tuesday called on Clinton to step down "if it can be shown that she was responsible for ordering U.S. diplomatic figures to engage in espionage in the United Nations" in violation of international agreements.
The State Department denies instructing diplomats to spy on their foreign counterparts. White House spokesman Robert Gibbs today dismissed Assange's statement.
"I think that's absurd and ridiculous. I think Secretary of State Clinton is doing a wonderful job. I think the foreign policy that she and the president are pursuing will make us stronger in the world, will make our country safer," Gibbs said.
Wikileaks has previously dumped classified military documents pertaining to the U.S.-led wars in Iraq and Afghanistan, but has come under increased scrutiny since it began releasing secret diplomatic cables on Sunday.
The Obama administration has warned the leaks will endanger lives, while talking down how the sometimes sordid revelations might hurt relations with important allies.
Several administration officials and members of Congress have suggested Assange be charged in U.S. court, despite being an Australian national who did not personally steal the documents.
Clinton has suggested Assange acted illegally and has promised "aggressive steps to hold responsible those who stole this information," and Attorney General Eric Holder said his threat to prosecute anyone involved in the obtaining and leaking the documents was just "saber rattling."
Interpol has joined the hunt for Assange, last believed to be in hiding in the United Kingdom, for an alleged sexual assault in Sweden.
Interpol issued an international alert for his arrest Tuesday because Swedish prosecutors said he has not made himself available for questioning.
Assange is wanted on suspicion of rape, sexual molestation and unlawful coercion. The exact nature of the allegations is unknown because formal charges have not been filed.
"Given that Sweden is a civilized country, I am reluctantly forced to conclude that this is a persecution and not a prosecution," Assange's lawyer Mark Stephens wrote the AP in an e-mail.