WikiLeaks founder Julian Assange delivers a speech from the balcony of Ecuadorean Embassy in London, Britain, on Dec. 20, 2012. (Xinhua/Bimal Gautam)

STOCKHOLM, May 19 (Xinhua) -- Swedish prosecutors announced on Friday that they would drop the rape case against WikiLeaks-founder Julian Assange, who has been under investigation of sex crimes allegedly committed in Sweden.

Sweden's director of public prosecution, Marianne Ny, filed a request to the Stockholm District Court to revoke Assange's arrest warrant that was issued seven years ago.

Assange, Ny said in a statement, "has escaped all attempts by the Swedish and British authorities to execute the decision to surrender him to Sweden in accordance with the EU rules concerning the European Arrest Warrant. My assessment is that the surrender cannot be executed in the foreseeable future."

Ny stressed that Assange's innocence has not been proven but that the investigation is being terminated because it is no longer possible to pursue it. That is partly due to the fact that the Swedish prosecutors have not been able to serve Assange a summons on suspicion, according to Ny.

Ny also said the Assange case is unique since the suspect took refuge in an embassy in a foreign country.

Assange, 45, has been holed up in Ecuador's London embassy since 2012, trying to avoid extradition to Sweden. He feared being extradited to the U.S. if sent to Sweden as he could face trial there over the leaking hundreds of thousands of secret U.S. military and diplomatic documents.

It was in August 2010 that Assange was detained in his absence during a visit to Sweden, where two women accused him of sexual assault, including rape. British police arrested him in London months later. He was first released on bail but later a British court determined that he should be handed over to Sweden.

After spending some time in house arrest, Assange managed to get to the Ecuadorian embassy in London, and was granted asylum. However, since he risked arrest if stepping out on British soil, Assange has been holed at the embassy for five years.

Swedish prosecutors continued to insist on questioning Assange in Sweden, but he was finally questioned by Equadorian prosecutors at the London embassy in November last year. Assange's testimony was then translated and handed over to the Swedes.

Earlier this month, Assange, via his lawyer, demanded that the arrest warrant against him be suspended since the United States had declared that they intended to imprison him.

"In view of the fact that all prospects of pursuing the investigation under present circumstances are exhausted, it appears that it is no longer proportionate to maintain the arrest of Julian Assange in his absence," Ny said on Friday. "Consequently, there is no basis upon which to continue the investigation."

The case against Assange could be resumed were he to return to Sweden before the statute of limitation for the crime he is suspected of runs out in 2020. He may also be arrested if he steps out of the Ecuadorian embassy, according to police in Britain, where authorities claim Assange broke his bail terms when he interrupted his house arrest to apply for political asylum at the London embassy.