Britain and the USA have an extradition treaty, so if Assange leaves the Ecuadorian Embassy where he's claimed asylum, the British could arrest him and send him to the US.
At a press conference Friday in Stockholm, Ny, chief of the Swedish Prosecution Authority, said she "has chose to discontinue the investigation" and call back the European arrest warrant for Assange.
Although, Swedish prosecutors said Friday they had dropped an investigation over a rape allegation, British police said he would be arrested if he left the Ecuadorean embassy in London where he has been holed up since 2012. Until that's confirmed either way, it's unlikely he will risk leaving the embassy.
Mr Assange originally faced three sex allegations, all of which he denied. His children had grown up without him, he said.
"That is not something I can forgive, or forget", he said, claiming he had suffered a "terrible injustice" while living under house arrest or hidden away inside the embassy without ever being charged with a crime.
However, London police issued a statement after the Swedish announcement making clear Assange was still wanted by them.
He sought asylum at the embassy over fears that if he is extradited to Sweden he would be sent onward to the US for prosecution over WikiLeaks' publication of secret documents, including thousands of USA diplomatic cables.
"It's a big victory day for Julian Assange", Mr Samuelson said in an interview.
Assange and WikiLeaks have repeatedly infuriated USA officials with the widespread release of sensitive secret documents related to military operations in Afghanistan and Iraq and diplomatic relations around the world.
During the presidential campaign in the United States, WikiLeaks came under criticism for distributing hacked emails from the Democratic National Committee.
Assange contends the United States should recognize his First Amendment rights as a journalist.
Assange has been granted asylum by Ecuador and has been able to evade justice because he is on Ecuador's sovereign territory by being in the embassy. He has refused to return to the Scandinavian country, citing risks he will be extradited to the United States over the release of secret documents. He did not take shouted questions from the reporters assembled outside and would not say if he plans to leave the embassy located in the posh Knightsbridge neighborhood.
It is not known if US officials are seeking Assange's arrest because of a possible sealed indictment.
United States authorities have prepared charges to seek his arrest, U.S. officials familiar with the matter told CNN last month.
Fritz said the process had dragged on for too long and that her client was "shocked" by the decision to drop it now.
Army Pvt. Chelsea Manning served seven years in prison for giving classified material to WikiLeaks.
He said American officials made up the case in an attempt to have him extradited.
"Westminster Magistrates' Court issued a warrant for the arrest of Julian Assange following him failing to surrender to the court on the 29 June 2012".
Mr Assange has not set foot outside the building, ultimately fearing he could be extradited to the USA over Wikileaks' publishing of huge amounts of classified information.
WikiLeaks tweeted: "UK refuses to confirm or deny whether it has already received a USA extradition warrant for Julian Assange. Focus now moves to the UK", WikiLeaks tweeted.
His supporters believe the sex crime allegations that have bedeviled Assange for years were politically motivated.
She said the case could be reopened if Assange returns to Sweden before the statute of limitations expires in 2020.