Updated at 3:45 p.m. ET
(CBS/AP) LONDON - WikiLeaks founder Julian Assange urged President Obama to end a so-called "witch hunt" against his secret-spilling website, appearing in public Sunday for the first time since he took refuge two months ago inside Ecuador's Embassy in London to avoid extradition to Sweden on sex crimes allegations.
The 41-year-old Australian, who has fought for two years against efforts to send him to Sweden for questioning over alleged sexual misconduct against two women, addressed several hundred supporters and reporters as he spoke from the small balcony of Ecuador's mission, watched by dozens of British police.
Ecuador's President Rafael Correa on Thursday granted Assange asylum 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, as by law it must meet the obligations of a European arrest warrant.
Embassy officials told CBS News correspondent Charlie D'Agata last week that they haveopportunities to question Assange at the embassy, but those offers have been turned down.
Praising Correa, Assange said "a courageous Latin American nation took a stand for justice," in offering him sanctuary, but did not refer to the Swedish allegations against him. Instead, he attempted to shift attention to what he claims are preparations in the U.S. to punish him for the publication by WikiLeaks of a trove of American diplomatic and military secrets including 250,000 U.S. Embassy cables that highlight sometimes embarrassing backroom dealings.
Assange and his supporters claim the Swedish case is merely the opening gambit in a Washington-orchestrated plot to make him stand trial in the U.S. something disputed by both Swedish authorities and the women involved.
"I ask President Obama to do the right thing. The United States must renounce its witch hunt against WikiLeaks," Assange said, speaking from a first-floor balcony decorated with an Ecuadorean flag, standing just yards away from British police officers.
"The United States must dissolve its FBI investigation. The United States must vow that it will not seek to prosecute our staff or our supporters," he said, wearing a formal blue shirt and red tie.
In purportedly targeting WikiLeaks, the U.S. risks "dragging us all into a dark, repressive world in which journalists live under fear of prosecution," Assange said.
The White House declined comment Sunday, but on Saturday it said Assange's fate is an issue for Sweden, Britain and Ecuador to resolve.
A Virginia grand jury is studying evidence that might link Assange to Pfc. Bradley Manning, the U.S. soldier who is awaiting trial on charges of aiding the enemy by passing the secret files to WikiLeaks. No action against Assange has yet been taken.
Assange also urged the U.S. to release Manning, but said: "If Bradley Manning really did as he is accused, he is a hero, an example to us all, and one of the world's foremost political prisoners."
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?"
Assange claimed to have won support from a host of other Latin American, Central American and South American nations including Brazil, Chile, Mexico and Argentina. However, Brazil and Colombia both insisted they haven't endorsed Ecuador's decision.
South America's foreign ministers were to meet in Guayaquil, Ecuador, on Sunday at the host nation's request to discuss the case. On Friday, foreign ministers of the Organization of American states are to convene in Washington to discuss the standoff.
Former Spanish Judge Baltasar Garzon, who is representing Assange, said Sunday that Ecuador could consider making an appeal to the International Court of Justice in the Hague to compel Britain to grant Assange safe passage out of the country.
Garzon, who won global fame for aggressively taking on international human rights cases, is appealing his conviction for overstepping his jurisdiction in a domestic corruption probe in Spain.
Tensions have risen between London and Quito over the case, after Britain appeared to suggest it could invoke a little-known law to strip Ecuador's Embassy of diplomatic privileges meaning police would be free to move in and detain Assange.
Assange claimed Britain had only refrained from carrying out the threat because of a vigil by his supporters outside the embassy. Ecuador's mission is a small apartment inside a larger building which houses offices and Colombia's Embassy. British police form a thick line outside, and are on guard in the building's shared lobby and staircases.
"Inside this embassy in the dark, I could hear teams of police swarming up inside the building through its internal fire escape," Assange said. "If the U.K. did not throw away the Vienna Convention the other night, it is because the world was watching." Under the 1961 Vienna Convention on Consular Relations, diplomatic posts are treated as the territory of the foreign nation.