Assange has been seeking refuge at the Ecuadorian Embassy in London since 2012, CNN reported.
Assange, an Australian national, has previously said that he feared that if he left the embassy he could end up being extradited and face the death penalty in the United States over allegations of revealing hundreds of thousands o secret U.S. military and diplomatic documents through WikiLeaks, CNN reported.
The move comes ahead of a Stockholm court's examination of a demand by Assange's lawyers that Sweden drop his European arrest warrant, the BBC reported.
American authorities have prepared charges to seek Arrange’s arrest, CNN reported, citing U.S. officials familiar with the matter.
The Metropolitan Police Service in London said after the news was announced that it remained obliged to arrest Assange should he leave the Ecuadoran embassy on a lesser charge of failing to surrender to a court, the BBC reported.
After the news was announced, WikiLeaks tweeted that the "focus now moves to the UK", saying the country had "refused to confirm or deny whether it has already received a U.S. extradition warrant for Julian Assange".