British Foreign Secretary William Hague
Julian Assange was holed up in Ecuador's London embassy on Friday with police guarding its exits after Britain warned that the diplomatic standoff over the WikiLeaks founder could go on for years.
Ecuador granted asylum on Thursday to Assange -- whose website enraged the United States by publishing a vast cache of confidential government files -- but Britain has vowed not to grant him safe passage out of the country, reports AFP.
British Foreign Secretary William Hague said his government was obliged under its own laws to extradite the Australian national to Sweden, where he is wanted for questioning over alleged sex crimes.
"No one, least of all the government of Ecuador, should be in any doubt that we are determined to carry out our legal obligation to see Mr Assange extradited to Sweden," Hague told a press conference on Thursday.
He admitted that the stalemate could continue for months or even years.
Some 20 British police were stationed outside the embassy early Friday, ready to arrest 41-year-old Assange if he leaves the building.
WikiLeaks condemned the continued police presence as "intimidation tactics".
A handful of supporters of the former computer hacker camped overnight outside the embassy in London's plush Knightsbridge district in a bid to "guard" Assange against any potential attempt to arrest him.
"We'll stay here as long as we have to," 26-year-old protester Baba Gena told AFP.
Assange has not left the embassy since June 19, when he walked in and claimed asylum.
WikiLeaks said on Twitter that he would give a statement in front of the embassy on Sunday, though it did not specify whether this would involve leaving the building and, if so, how he would do so without being arrested.
Under normal diplomatic procedures, embassies are considered the territory of the countries they represent and cannot be entered without permission.
Britain has angered Ecuador by suggesting it could invoke a domestic law allowing it to breach the usual rules and go in to arrest Assange.
This would challenge a fundamental principle of the diplomatic system, and the threat has left Britain in unchartered legal waters.
WikiLeaks spokesman, Kristinn Hrafnsson told AFP the move would "risk upsetting diplomatic relations all over the world".
"Hopefully, we will see the decision resolved in a civilised manner," he added.
A Foreign Office spokesman said Friday that Britain was "committed to working with the Ecuadorans to solve this matter amicably".
He added: "We will not be commenting on our meetings or contact with them."
Ecuador has called a meeting of foreign ministers from the South American regional bloc UNASUR on Sunday, while the Organization of American States is to decide Friday whether to call a meeting of its foreign ministers.
"Nobody is going to scare us," Ecuador's President Rafael Correa said on his Twitter account, minutes before the decision to grant asylum was announced.
Ecuadoran Foreign Minister, Ricardo Patino said his government granted asylum after Britain, Sweden and the United States refused to provide guarantees that Assange would not be passed on from Sweden to the US.
In 2010, WikiLeaks published an enormous cache of US military documents on the war in Iraq and Afghanistan and diplomatic cables that deeply embarrassed Washington.