By Daniel Dickson and Simon Johnson
STOCKHOLM (Reuters) - Swedish prosecutors want to question Julian Assange in London over allegations of sexual assault, potentially ending an impasse that left the WikiLeaks founder holed up for almost three years in Ecuador's embassy.
Swedish prosecutors said on Friday they had asked for Assange's approval to question him in London, a U-turn after years of insisting he must go to Stockholm for questioning about alleged assaults against two women in 2010.
Assange denies the allegations, which are not related to WikiLeaks' publication of U.S. military and diplomatic documents, also in 2010. He refused to go, arguing Sweden could send him on to the United States where he might face trial.
One of Assange's lawyers said he welcomed the request but expressed concern the process could take time because approval was needed from British and Ecuadorian authorities.
"He has been nagging for this for four years. He wants nothing more than to have an opportunity ... to give his version of what happened and to clear his name," Assange's lawyer Per Samuelson told Reuters.
Ecuador's embassy in London could not immediately be reached for comment.
Assange, an Australian citizen, has been unable to leave Ecuador's embassy since claiming asylum there in 2012.
Even if Sweden drops the investigation, he faces arrest by British police for jumping bail granted while the UK courts considered a European arrest warrant issued by Sweden.
Samuelson said Assange and his lawyers had to discuss the request from Swedish prosecutors, who also want to sample his DNA, before responding.
A Swedish appeals court late last year upheld a detention order on Assange, but said prosecutors had not made enough effort to question him.
The main reason for prosecutors' change of heart is that several crimes Assange is suspected of are subject to a statute of limitations expiring in August.
Prosecutor Marianne Ny said she still believed questioning him at the embassy would lower the quality of the interview and he would need to be in Sweden should the case come to a trial.
"Now that time is of the essence, I have viewed it therefore necessary to accept such deficiencies to the investigation," she said in a statement.
Sweden's Supreme Court is currently weighing whether to hear his request to lift the warrant for Assange's arrest and has asked the prosecutor to submit an opinion before a decision can be taken.
London's police chief said last month the cost of keeping watch on Assange was a drain on police resources and the operation was under review.
(This version of the story was corrected to clarify in paragraph 8 that Sweden has not charged Assange)