On Monday, it emerged that Assange may be ready to return to Sweden to face questioning over claims by two women that he raped and sexually assaulted them in August 2010.
However, he would only consider giving up his lengthy battle to avoid extradition to Sweden if officials in Stockholm guaranteed that he wouldn't be turned over to the United States to face espionage and conspiracy charges over secret US documents previously published by WikiLeaks.
But an official with Sweden's Ministry of Justice said that, according to current legislation, Sweden couldn't provide Assange with the guarantees he's currently seeking.
"Any such guarantee doesn't exist," Cecilia Riddselius, a staff member with the ministry's Division for Criminal Cases and International Judicial Cooperation, told the Dagens Nyheter (DN) newspaper.
"After having worked on these issues for ten years, I can't see how it could become reality."
Riddselius emphasized that the matter remained hypothetical and that her assessment was restricted to that of a government civil servant.
Currently, there is no formal request or indication that the United States is interested in extraditing Assange, who has been holed up in the Ecuadorian embassy in London since last Wednesday waiting for the South American country to process his request for political asylum.
At the weekend, Australian foreign minister Bob Carr rejected claims that Washington is keen to get Assange, saying there was "no hint" of a plan to extradite the 40-year-old former compuer hacker to the United States.
According to Riddselius, countries can ask for different sorts of guarantees related to extradition cases, but the guarantees are restricted to covering the sort of treatment someone might receive once extradited, such as guarantees the person wouldn't be tortured or sentenced to the death penalty.
But, she said, Sweden couldn't guarantee Assange that he wouldn't be extradited to the United States ahead of his possible arrival in Sweden.
For the moment, officials in Sweden are standing by awaiting further developments in the case.
"We're waiting to see how Ecuador acts," Riddselius told DN.