Wikileaks founder Julian Assange portrayed himself Sunday as a victim of an American “witch hunt” over his secret-spilling website in a defiant address from the balcony of an embassy where he has holed up to avoid extradition to face sex assault allegations.

Surrounded by British police who want to detain him, Assange made no mention of the sex assault case in Sweden or how long he would remain in Ecuador's embassy in London, where he took refuge two months ago. Instead he shifted focus to the U.S., accusing the government of targeting him for revealing a trove of American diplomatic and military secrets.

“I ask President Obama to do the right thing. The United States must renounce its witch hunt against WikiLeaks,” Assange said, wearing a formal blue shirt and red tie in front of the Ecuadorean flag.

“The United States must vow that it will not seek to prosecute our staff or our supporters,” he said, referring specifically to Pfc. Bradley Manning, who awaits trial in Virginia in the scandal.

The U.S. risks “dragging us all into a dark, repressive world in which journalists live under fear of prosecution,” Assange said

Assange and his supporters claim the Swedish case is the first move of a Washington-orchestrated plot to make him stand trial in the U.S., which Swedish authorities dispute.

The White House declined comment Sunday, but on Saturday said Assange's fate is an issue for Sweden, Britain and Ecuador to resolve.

Assange, a 41-year-old Australian citizen, shot to international prominence in 2010 when his WikiLeaks website began publishing its huge cache of American secrets, including 250,000 U.S. Embassy cables that highlighted sometimes embarrassing backroom dealings.

As he toured the globe to highlight the disclosures, two women accused him of sex offenses during a trip to Sweden. Assange has said the sex with the women was consensual and denied wrongdoing, but has fought off efforts to return him to Sweden for questioning for two years.

Ecuador's President Rafael Correa granted Assange asylum Thursday, and he remains out of reach of British authorities while he is inside the country's embassy. Britain insists that if he steps outside, he will be detained and sent to Sweden.

Assange praised Ecuador Sunday as “a courageous Latin American nation took a stand for justice,” in offering him sanctuary. He suggested he had won the support of a host of Latin American nations _ including Brazil, Colombia, Chile, Mexico and Argentina. Of those five, however, only Argentina has endorsed Ecuador's decision to grant asylum.

Assange urged the U.S. to release Manning, the U.S. soldier charged with aiding the enemy by passing the secret files to Wikileaks. A Virginia grand jury is studying evidence that might link Assange to Manning.

Calling Manning “one of the world's foremost political prisoners,” Assange said: “If Bradley Manning really did as he is accused, he is a hero, an example to us all.”

The WikiLeaks founder give no indication of how he believes the stalemate over his future may be resolved, though he said he hoped to be “reunited soon” with his two children.

“I think these allegations are just a way of getting to him,” said Laura Mattson, a 29-year-old supporter from London who joined a raucous crowd outside the embassy. “Is it about the charges or is it about silencing WikiLeaks?”

South America's foreign ministers met in Guayaquil, Ecuador, on Sunday at the host nation's request to discuss the case. (AFP)