Ecuador's foreign minister Maria Fernanda Espinosa said Assange was naturalised as a citizen on 12 December, at his request.
Assange, 46, has previously expressed concern that if he leaves the Ecuadorian embassy in London he could end up being extradited to the United States, where he fears facing the death penalty over allegations of revealing government secrets through WikiLeaks.
According to WaPo, Ecuador's government has confirmed that Assange will remain in the embassy until there is a guarantee that he will be secure in leaving.More news: Edge ST With EcoBoost Twin-Turbo
"No solution will be achieved without worldwide cooperation and the cooperation of the United Kingdom, which has also shown interest in seeking a way out", she told foreign correspondents in Quito, according to Agence France-Presse. Concerns have been raised over whether Assange could soon be forced out of the embassy, as Ecuador reportedly looks to end the "unsustainable" standoff with the United Kingdom authorities. Quito has said naturalization should provide Assange with another layer of protection.
The request for diplomatic status was made on behalf of the 46-year-old campaigner by the Ecuadorean government, which has reportedly issued a passport to the Australian national after he had sought political asylum from the South American country five and a half years ago. But this week has been a confusing one for the WikiLeaks founder, as rumours have swirled about him possibly leaving the embassy whether he wanted to or not.
Espinosa expressed irritation at recent news reports, saying she felt "obliged to make statements about a matter" that needed to "be managed with prudence and caution". She added that Ecuador was looking to resolve the impasse in a "dignified" way.
On Thursday, Espinosa said Ecuador was exploring a variety of possible resolutions to the dispute.