Amnesty International has urged Sweden to "break the current impasse" in the Julian Assange extradition case by giving him assurances that he will not be handed over to the U.S., according to BBC News.

The Wikileaks founder, who is living at Ecuador's London embassy, is fighting UK efforts to send him to Sweden.

He faces questioning over sex assault claims, which he denies.

Amnesty said fears he will face a U.S. trial over Wikileaks "have played no small part in the current stand-off".

It added that it has no evidence that Sweden plans to extradite Mr Assange to the US but if such a "forced transfer" did take place, it believed he would be exposed to a "real risk of serious human rights violations".

Assange, 40, who has now been at Ecuador's embassy for 100 days, has been granted asylum by the country.

In a statement, Nicola Duckworth, Amnesty's senior director for research, said: "If the Swedish authorities are able to confirm publicly that Assange will not eventually find himself on a plane to the USA if he submits himself to the authority of the Swedish courts then this will hopefully achieve two things.

"First, it will break the current impasse and second it will mean the women who have levelled accusations of sexual assault are not denied justice.

"It is vital that states show they are serious about dealing with allegations of sexual violence and that they respect both the rights of the women who made the complaints and the person accused."