- Julian Assange is effectively confined to the embassy of Ecuador in London
- The founder of WikiLeaks hasn't been seen since June, or spoken in public since March
- Ecuador's president says Britain threatened to raid the embassy to arrest Assange
- Assange seeks to avoid extradition to Sweden to face questions about alleged rape
London (CNN) -- WikiLeaks founder Julian Assange is expected to break months of silence Sunday from the Ecuador Embassy in Britain, where he fled to avoid extradition to Sweden to face questioning about alleged sex crimes.
About 40 London police officers stood guard outside the embassy ahead of the expected appearance, while about a dozen Assange supporters turned out. Both groups were outnumbered by the media and by curious shoppers from the upscale stores in the area.
Assange has been holed up in the embassy for two months.
Ecuador raised the stakes in its diplomatic row with the United Kingdom on Thursday, officially offering Assange asylum in the South American country -- but the British say they will not give him safe passage out of the embassy.
The Foreign Office says Britain has a legal obligation to hand him over to Sweden after Assange's legal efforts to avoid extradition were rejected in British courts up to the Supreme Court.
Sunday marks two months since Assange fled to the embassy. Monday marks two years since Swedish prosecutors first issued a warrant for his arrest, alleging that he raped one woman and sexually molested another.
Assange says the charges are politically motivated and tied to the work of his website, which facilitates the publication of secret documents. He has published hundreds of thousands of pages of American government diplomatic cables and assessments of the wars in Afghanistan and Iraq.
Assange is scheduled to speak Sunday afternoon from the embassy in London, where he has been living, effectively confined to the diplomatic mission -- a suite of rooms covering half of one floor of a townhouse in a posh London neighborhood south of Hyde Park.
His statement comes as foreign ministers from various South American countries gather in Ecuador to discuss his fate.
The dispute between London and Ecuador exploded when the British Foreign Office, in a letter to Ecuadorian officials, cited a little known law that could temporarily suspend the embassy's diplomatic protection and allow authorities to enter and arrest Assange.
Assange protests in London President Rafael Correa on Saturday slammed Britain's behavior toward Ecuador, describing it as "intolerable" and "unacceptable."
Standoff at Ecuador embassy over Assange "Who do they think they're dealing with?" Correa asked rhetorically during his weekly address. "They don't realize Latin America is free and sovereign. We won't tolerate interference, colonialism of any kind."
Can Assange leave London? The president said Ecuador had sought, but did not receive, guarantees that Assange would not be extradited to a third country.
Waiting for Assange to make a move Assange, an Australian, and his supporters claim a U.S. grand jury has been empaneled to consider charges against him. They fear if he is extradited to Sweden, he could be sent to the United States next .
Sweden angrily rejected the allegation on Thursday.
"Sweden does not extradite individuals who risk facing the death penalty," the Foreign Ministry said after Ecuador granted Assange asylum.
Correa is seeking support on the issue from foreign ministers of the the Union of South American Nations and the leftist Bolivarian Alternative for the Americas (ALBA), who are gathered in Guayaquil, Ecuador, this weekend.
ALBA, whose membership includes Venezuelan President Hugo Chavez, warned Britain on Saturday against raiding the embassy.
"We warn the government of the United Kingdom that it will face grave consequences around the world if it directly breaches the territorial integrity of the Embassy of the Republic of Ecuador in London," according to a statement read by Foreign Minister Nicolas Maduro on behalf of ALBA nations.
Assange was arrested in Britain in 2010 because Swedish authorities wanted to question him about the allegations. Two women accused him of sexually assaulting them during an August 2010 visit to Sweden in connection with a WikiLeaks release of internal U.S. military documents.
Assange denies the allegations and argues they are in retribution for his organization's disclosure of American secrets.
Publicly silent since March, Assange is expected to speak two months to the day since he sought asylum, according to WikiLeaks' official Twitter feed.
CNN's Norman Powell, Chelsea J. Carter and Per Nyberg contributed to this report.
