Wikileaks founder Julian Assange is expected to find out whether Ecuador will grant him asylum later today.
The announcement follows a dramatic claim by Ecuador's foreign minister that Britain threatened to storm his country's London embassy to arrest Mr Assange.
Ricardo Patino told a news conference Ecuador had received a written threat from the UK that "it could assault our embassy" if the 41-year-old was not handed over.
Mr Patino released details of a letter he said was delivered through a British embassy official in the capital of the South American country, Quito.
The letter said: "You need to be aware that there is a legal base in the UK, the Diplomatic and Consular Premises Act 1987, that would allow us to take actions in order to arrest Mr Assange in the current premises of the Embassy.
"We sincerely hope that we do not reach that point, but if you are not capable of resolving this matter of Mr Assange's presence in your premises, this is an open option for us."
But the British Foreign Office has said in a statement: "We have an obligation to extradite Mr Assange and it is only right that we give Ecuador the full picture.
"Throughout this process we have drawn the Ecuadorians' attention to relevant provisions of our law ... We are still committed to reaching a mutually acceptable solution."
Ecuador has said it hopes to announce a decision this week, possibly later today, on Mr Assange's asylum request.
The Australian, who published thousands of sensitive US documents including diplomatic cables and military dispatches via the internet, took refuge in the embassy two months ago to avoid extradition to Sweden, where he faces questioning for alleged sexual misconduct.
Mr Assange says he fears deportation to the United States, which may seek to try him for his website's release of a trove of secret documents.
A number of police officers were reported to have arrived outside the embassy on Wednesday evening (yesterday), close to the Harrods store in Knightsbridge, as the diplomatic row blew up.