Moves to arrest WikiLeaks head as site fights on

And there was speculation that an arrest of the site's founder Julian Assange might be imminent, after Swedish authorities refiled an international warrant with additional information requested by the Metropolitan Police.

The 39-year-old Australian former computer hacker, who is understood to be in the UK, today answered questions on The Guardian's website, and hailed as "an unparalleled hero" the soldier suspected of passing 250,000 secret US diplomatic papers to WikiLeaks.

Mr Assange praised US Army intelligence analyst Bradley Manning, 23, without confirming he was the source of the leaks.

The latest tranche of confidential documents to appear on the website included cables from the US embassy in Afghanistan reporting criticisms of Britain's military operations in the country by President Hamid Karzai and a top Nato commander.

And cables from the London embassy showed that former US ambassador Robert Tuttle had written Gordon Brown's premiership off as "abysmal" within a year of him becoming Prime Minister.

The website moved to the Swiss address wikileaks.ch after the American company providing its domain name, EveryDNS.net, cut off service. WikiLeaks had turned to EveryDNS and servers in Europe after Amazon stopped hosting the site on Thursday.

Mr Assange said: "The threats against our lives are a matter of public record, however, we are taking the appropriate precautions to the degree that we are able when dealing with a superpower."

Mr Assange is wanted for questioning in Sweden on suspicion of rape, sexual molestation and unlawful coercion, following complaints – which he strongly denies – made by two women in August.

An international warrant for his arrest was issued by Sweden last month, but British police requested more information.

It is understood that this has now been provided, although the Metropolitan Police refused to discuss whether officers were preparing to arrest Mr Assange.

Mr Assange's UK lawyer said: "The police have given us an undertaking that they will contact us if they want to get in touch with Julian. At this point in time nobody has."

The leaks sparked indignation in Britain after secret cables from the US embassy in Kabul reported that Mr Karzai said Britain was "not up to the task" of securing the southern province of Helmand and suggested the job would be better given to the US.

US General Dan McNeill, who led Nato forces in Afghanistan in 2007/08, was said to have been "dismayed" by British efforts which "made a mess of things".

And Helmand governor Gulab Mangal was reported to have criticised British troops for failing to get out of their bases and engage with local people.

Colonel Stuart Tootal, former commander of 3 Para, the first battle group to be sent into Helmand in 2006, said he was "disappointed" by the disclosures but insisted they were out of date.

"It's been challenging – the resources, the initial approach was wrong," Col Tootal told the BBC. "Now we've got 30,000 Nato troops, British and American, who are all doing a fantastic job and we mustn't lose sight of this."

Anthony Philipson, whose son James was one of the first British troops to die in the province, said: "Yes, the place is still a hotbed of violence, but I think it always will be."

But Ian Sadler, of Exmouth, whose 21-year-old son Jack died in Helmand in 2007, said he welcomed the WikiLeaks release because it showed what officials really believed.

"We usually only get the politically-correct version of the truth," said Mr Sadler.