WikiLeaks founder Julian Assange at the Ecuadorian embassy in London (Reuters)

Whisteblowing website WikiLeaks has launched a fundraising campaign in the US - on the day that a group of founder Julian Assange's wealthy backers could lose £140,000.

Ahead of November's American presidential election, the new fundraising campaign urges voters to "help WikiLeaks run the United States over the next four years". He said the funding would enable WikiLeaks to continue providing the kind of revelations that have helped shape US government policies over recent years.

As Barack Obama and Mitt Romney square up for their first televised debate, WikiLeaks claimed that key recent events such as the US withdrawal from Iraq were triggered by the site's revelations about American involvement in the war-torn country rather than the actions of any politician.

Assange spoke out in support of the fundraising drive in a video propbaly recorded at the Ecuadorian Assembly, where he has sought asylum from extradition to face rape charges in Sweden.

Assange said: "Cast the only vote that matters. Vote with your wallet, vote WikiLeaks.

"Government and institutions know that knowledge is power. That is why they spend so much money attempting to conceal their plans and actions from all of us. They know that together we can force them to act differently.

"This election, you can choose to help us run America over the next four years."

As part of the "Vote WikiLeaks" campaign, the organisation also provides its supporters with directories on how to fund Assange's legal defence costs.

£140,000 at stake

Meanwhile, a judge at Westminster magistrates court will rule on whether a group of wealthy individuals who provided sureties when Assange was originally bailed will lose their money.

A group of nine backers, including the Marchioness of Worcester, Lady Caroline Evans, and Cambridge scientist Sir John Sulston, raised a total of £140,000 to guarantee Assange's bail conditions.

However, following Assange's bid for asylum in the embassy, a court ruled he had breached bail conditions. On 4 September, judge Howard Riddle issued an ultimatum giving the nine backers a month to persuade Assange to give himself up - or risk forfeiting their share of the surety.

A separate group of backers, including Jemima Khan, Michael Moore and film director Ken Loach, has already lost £200,000 as a result of Assange's breach. Foreign secretary William Hague said he would not be allowed safe passage out of the United Kingdom.

Ecuador's president, Rafael Correa, has said that Assange can remain in the embassy indefinitely.