Julian Assange has pleaded not guilty to a charge at Westminster Magistrates' Court that he failed to surrender to custody as required for an extradition order to Sweden.
The WikiLeaks founder has also been found guilty of breaching his bail and faces a jail sentence of up to 12 months when he is sentenced at Crown Court.
Mr Assange had been further arrested on behalf of US authorities having been removed from the Ecuadorian embassy by the Metropolitan Police on Thursday morning.
A Scotland Yard spokesman said Assange has "been further arrested on behalf of the United States authorities, at 10:53hrs after his arrival at a central London police station".
"This is an extradition warrant under Section 73 of the Extradition Act," a spokesman said.
"He will appear in custody at Westminster Magistrates' Court as soon as possible."
Police officers were invited into the embassy by the Ambassador after the Ecuadorian government withdrew its offer of asylum to Mr Assange, according to Scotland Yard.
Ecuador's president Lenin Moreno said on Twitter: "In a sovereign decision Ecuador withdrew the asylum status to Julian Assange after his repeated violations to international conventions and daily-life protocols."
he WikiLeaks founder, 47, was removed from the embassy on a warrant issued for failing to surrender to the court.
The warrant was initially issued on June 29, 2012.
The Minister of State for Europe and the Americas, Sir Alan Duncan has said it was "absolutely right that Assange will face justice".
In a statement, he said: “It is absolutely right that Assange will face justice in the proper way in the UK. It is for the courts to decide what happens next.
“We are very grateful to the Government of Ecuador under President Moreno for the action they have taken.
“Today’s events follow extensive dialogue between our two countries.
“I look forward to a strong bilateral relationship between the UK and Ecuador in the years ahead.”
Dr Alan Mendoza, Executive Director of the Henry Jackson Society, advocated Mr Assange to be extradited to the US.
He said: “If, as has been reported, Mr Assange faces charges in the US, the British Government must urgently enable his extradition there following his departure from the Ecuadorian Embassy.
"The actions of WikiLeaks have cost the lives of Western troops, bolstered the interests of Russia and China, and jeopardised the security of people across the free world.
"At the same time, Mr Assange’s continued residency in London has impacted the UK/US relationship."
The Met Police have said that Mr Assange will remain in custody at a central London police station until he can be presented to the court.