In a telephone interview with Australian Broadcasting Corp radio from the Ecuador embassy in London, Assange said he fears that if sent to Sweden, he would then be extradited to the United States where he believes he could face criminal charges punishable by death.
On June 14, the British supreme court had dismissed his final legal bid to block his extradition to Sweden.
While inside Ecuador's embassy, Assange is out of the reach of British authorities. However, the police are poised to arrest him the moment he steps foot outside the building. British police have confirmed he will be arrested for breaching the terms of his bail, which include an overnight curfew at a registered address.
WikiLeaks, founded by Assange, which facilitates the anonymous leaking of secret information, has published some 2,50,000 confidential US diplomatic cables, causing embarrassment to the government and others. It has also published hundreds of thousands of classified US documents relating to the conflicts in Iraq and Afghanistan.
"The Swedes announced publicly, that they would detain me, in prison, without charge while they continued their so-called investigation," Assange said.
"We had heard that the Ecuadorians were sympathetic in relation to my struggles and the struggles of the organisation with the United States, and the ability to exercise that option was at an effective end," he said.
Assange acknowledged that the US had indicated that it would not extradite him, but said officials were "being very careful with their words".
"Their careful statements reflect that the [US] department of justice is not able to formally confirm or deny the existence of the grand jury -- it's a policy with all grand juries. But there are subpoenas everywhere, there are witnesses who have come out on public record," Assange said.
"We have received subpoenas -- the subpoenas mention my name. In the past month, two people have been detained at the US airport by US officials, interrogated by the Federal Bureau of Investigation. They ask questions about me and my organisation, ask [them] to become informers. This is a hot, ongoing, active investigation -- and as of two weeks ago," he said.
During the interview, Assange also accused the US and Australian governments of using "slimy rhetoric" in his case and dismissed repeated Australian government claims that he has been receiving ongoing consular assistance.
Meanwhile, leftist Ecuadorean President Rafael Correa reiterated that his government plans to do a very thorough analysis of Assange's application before making a decision.
The leftist leader, who has often been at odds with Washington, said his government was studying Assange's claim that he could be extradited from Sweden to the United States on political grounds and possibly sentenced to death.
"We could not allow that a person who has asked for asylum may have to face the death penalty, especially for political crimes," Correa told reporters.