JULIAN Assange has called on the United States to stop the "witch-hunt" of him and his followers as he spoke publicly for the first time since seeking asylum in the embassy of Ecuador in London.

Addressing a crowd from the diplomatic safety of a balcony just a couple of metres above street level, the 41-year-old thanked the Ecuadorian government for giving him asylum and his followers for backing him.

Dressed in a smart blue shirt and red tie, a straight-faced Assange read from a prepared speech.

He said when it became clear that Britain was looking at its option of entering the diplomatic sanctity of the embassy, his supporters rallied.

"On Wednesday night, after a threat was sent to this embassy, the police descended on this building. You came out in the middle of the night to watch over it, and you brought the world's eyes with you,” he said.

"Inside this embassy in the dark, I could hear teams of police swarming up inside the building through its internal fire escape. But I knew there would be witnesses, and that is because of you.

"If the UK did not throw away the Vienna Conventions the other night, it is because the world was watching. And the world was watching because you were watching.

"So the next time that somebody tells you that it is pointless to defend those rights that we hold dear, remind them of your vigil in the dark before the embassy of Ecuador. Remind them how, in the morning, the sun came up on a different world, and a courageous Latin American nation took a stand for justice."

I ask President Obama to do the right thing - the US must renounce its witch-hunt against WikiLeaks

He urged the US renounce its witch-hunt.

"Will it return to and reaffirm the revolutionary values it was founded on or will it lurch off the precipice, dragging us all into a dangerous and oppressive world in which journalists fall silent under the fear of prosecution and citizens must whisper in the dark?

"I say it must turn back. I ask President Obama to do the right thing: the United States must renounce its witch-hunt against WikiLeaks."

Assange was given asylum last week amid moves by British authorities to extradite him to Sweden to face allegations of sexual assault. Assange denies the allegations and fears being transferred to America where he could face life in jail for the 2010 WikiLeak revelations of thousands of secret diplomatic cables.

He thanked his family, including his children "who have been denied their father".

"Forgive me, we will be reunited soon," he said.

media_camera WikiLeaks founder Julian Assange makes an address from inside the Ecuadorian embassy in London, as police and media line the street outside. Assange called on United States President Barack Obama to end a "witch hunt" against the secret-spilling WikiLeaks organization. AP Photo / Sean Dempsey

After his address, a core of Hispanic supporters chanted and sang for hours in his honour and released balloons in the red, blue and yellow colours of Ecuador. The world press contingent itself numbered in the hundreds.

As the moment of his anticipated balcony appearance approached, 100 police officers formed two lines in front of the embassy fearing a surge in the crowd or the unlikely possibility there would be some form of an attempt at a distraction to allow Assange to escape. Neither occurred.

Assange looked pale and gaunt almost frail as he read from a prepared speech. After his words to stood for a moment to enjoy the moment of rapturous applause and cheers, gave a thumbs up then moved inside.

There was no mention as to how he hoped to leave the embassy or when.

Mr Assange's appearance on the balcony of the Ecuadorean embassy in London was seen as an attempt to avoid arrest. The Australian national, who won political asylum from Ecuador last Thursday, is wanted by Sweden for questioning over alleged sexual misconduct.

With police officers primed to detain him, Mr Assange had to find a way of speaking publicly without setting foot outside.

Mr Assange also called for the freedom of whistleblower Bradley Manning, who allegedly leaked a trove of classified US army documents to WikiLeaks. Mr Assange said Mr Manning had spent 815 days in prison without trial.

"If Bradley Manning did as he is accused he is a hero and an example to all of us and one of the world's foremost political prisoners," Mr Assange said.

After the speech, Mr Assange's mother Christine said it would "inspire millions". She watched the speech from her Brisbane home.

"It was fabulous," she told AAP. "He looks so well, he sounds well, he puts so many so-called leaders to shame. He's written and read a brilliant speech ... which has inspired millions."

media_camera Julian Assange gives the thumbs up to crowd after his statement to the media and supporters on a balcony of the Ecuadorian Embassy in central London. AP photo/Sang Tan

There were several delays as technicians battled with the set up of a microphone and protestors enjoyed the limelight but then shortly after 2.15pm (11.15pm AEST) he emerged to rapturous cheers and applause from the some 2000 standing before him.

"I am here today because I can't be there today," he said, pointing to the street.

His high profile lawyer Baltasar Galzon emerged at 10pm AEST to make a statement that his client was in a "fighting spirit".

"Julian Assange has always fought for truth and justice and has defended human rights and continues to do so, he demands that WikiLeaks and his own rights be respected," he said.

A series of speakers for a "broad coalition" of supporters then spoke to rousing applause as they detailed the peaceful settlement Ecuador and WikiLeaks supporters wanted.

They used the worldwide spotlight, and in many instances live broadcasts, to bring on a number of speakers to read speeches, and proclaim solidarity and the public's right to know, including reading a statement from Australian journalist and activist John Pilger.

media_camera Surrounded by British police officers, WikiLeaks founder Julian Assange makes a statement to the media and supporters at a window of Ecuadorian Embassy in central London. AP Photo/Sang Tan

A phalanx of more than 100 uniformed police officers stood shoulder-to-shoulder out the front of the embassy building, a team of about eight inside in the foyer and many more officers in vans parked on side streets and at the back of the block.

They were also on the roof with binoculars looking down - as was a police helicopter that buzzed overhead shortly before he spoke, coordinating movements. Police had been told they could arrest Mr Assange if he stepped onto public land.

Mr Assange told more than 2000 supporters, media and the curious that had been gathering since mid-morning, and a few who have been camping 24/7 out the front of the building since last week, he appreciated their overwhelming support.

For most of the morning, supporters with mega phones played music and enticed Sunday lunchtime shoppers and tourists away from the busy upmarket Knightsbridge strip, including from the next door department store Harrods, to join the movement.

"If you want transparency in the world and end the secrecy, if you stand for freedom, come and join us here," they beckoned and many obliged, particularly when the curtain parted on the balcony as technicians tested PA systems.

Most, however, simply got their photos taken in front of the colourful spectacle of protestors and the large throng of world press and moved onto lunch.

Protesters were highly organised distributing leaflets, balloons and bottles of water to its troops, standing for hours in what at one point was one of the hottest days in London this year with the mercury topping 29 degrees.

Some pamphlets were critical of Australia's response to not protect its citizen and the crowd cheered loudly when the country was condemned for failing to protect its "Melbourne-born son", prompting Ecuador to adopt him.

Britain has declared it will not allow Mr Assange safe passage out of the embassy and vowed to live up to its international extradition treaties and send him to Sweden.

Mr Assange, who has been living in a small back room of the embassy since June 19, was granted asylum last week after British courts ruled he should be extradited to Sweden to face allegations of sexual assault. Ecuador granted him asylum on the grounds it was not satisfied Swedish authorities would not extradite him to the US where he faces charges of releasing 250,000 secret US diplomatic and military cables. The penalty carried life in jail, or the death penalty.

Ecuador meanwhile said yesterday it may consider appealing to the International Court of Justice in the Hague to force Britain to allow safe passage for Mr Assange to its shores.The former Spanish Judge Mr Garzon said this may be the only way forward in the impasse which has seen Britain threaten to suspend Ecuador's diplomatic immunity in order to arrest Mr Assange.

media_camera WikiLeaks founder Julian Assange with his legal adviser Baltasar Garzon talk inside the Ecuadorian embassy in London.

Ecuadorian President Rafael Correa said his country never wanted to impede the investigation of a supposed crime.

"What we wanted to impede is the extradition to a third country," he said, not ruling out taking the standoff with the British authorities to a higher authority. A coalition of South American foreign minsters are to meet in Washington to discuss the implications of the Assange affair.

Meanwhile, posters questioning Australia's perceived inaction over its citizen continue to be placed outside the embassy in central London where Mr Assange is holed up. Supporters are also being urged to write to Australia's High Commission on behalf of the activist.

Fresh food and vegetables are being delivered daily to the compound and yesterday some select friends and a video team were allowed access into the embassy to see Mr Assange. Even a chocolate cake was delivered for the man who is virtually a prisoner in his tiny makeshift bedroom in the embassy.

A large contingent of police continue to ring the building housing the first-floor embassy with orders to arrest Mr Assange if he steps out onto public land, as opposed to any space deemed the territory of Ecuador.

WikiLeaks supporters have maintained a 24-hour vigil outside the embassy amid fears officers will move into the premises and forcibly remove Mr Assange sometime in the night.

British Foreign Secretary William Hague said this was not his intention and he hoped for a diplomatic solution.

The powerful Latin American Organization of American States (OAS) will hold a foreign ministers' meeting today (Monday) over the Assange affair and specifically Britain's threat to breach diplomatic protocols to enter the embassy.

"The central issue is not the right of asylum, it is the inviolability of embassies," OAS Secretary General Jose Miguel Insulza said.

Originally published as Assange calls for 'end to witch-hunt'