WikiLeaks founder Julian Assange is inside the Ecuadorian Embassy in London seeking political asylum, sources told the Press Association.
He walked into the embassy, in London's Knightsbridge district, and asked for asylum under the United Nations Human Rights Declaration.
A man speaking from the embassy said over the telephone that Mr Assange had arrived at the embassy on Tuesday and was requesting political asylum.
Ecuador's foreign minister Ricardo Patino also confirmed the Australian had taken refuge at its embassy and that the country's government was weighing up the request.
A message was posted on the Wikileaks Twitter account, saying: "ALERT: Julian Assange has requested political asylum and is under the protection of the Ecuadorian embassy in London."
A second read: "We will have more details on the Ecuadorian situation soon."
The dramatic move followed a long-running legal bid by Mr Assange, 40, to halt his extradition to Sweden, where he faces sex crime allegations.
But Mr Assange was given time to consider the judgment.
The Swedish authorities want him to answer accusations of raping a woman and sexually molesting and coercing another in Stockholm in August 2010 while on a visit to give a lecture.
Assange, whose WikiLeaks website has published a mass of leaked diplomatic cables that embarrassed several governments and international businesses, says the sex was consensual and the allegations against him are politically motivated.