Whistleblower website Wikileaks has made contact with the US government over claims that an American serviceman is one of its sources.

Soldier Bradley Manning has been held for three weeks without formal charge.

The US is investigating claims that he passed confidential information to Wikileaks.

Site editor Julian Assange told BBC News that, so far, the US authorities have not yet been in touch with him.

He said that lawyers representing Wikileaks have been in touch with the US administration but that neither the Department of State nor the Department of Defense had made any attempt to approach the site.

In spite of the silence from the US, Mr Assange said he felt it was "important to have a channel open in these matters".

No conversations could take place which might reveal the identity of any source, he added.

Mr Manning was identified as an alleged Wikileaks source after former hacker Adrian Lamo, in whom he had confided, contacted the authorities.

During a series of conversations conducted online, Mr Lamo claims that Mr Manning revealed he had passed 260,000 US diplomatic cables and two confidential military videos to Wikileaks.

US state department spokesperson PJ Crowley has said that the Bureau of Diplomatic Security was examining one or more hard drives used by Mr Manning in Iraq.

Not proved

Wikileaks said it did not know whether Mr Manning, who had served in Iraq as an army intelligence analyst, was the source of the leak as the website does not keep personal records of the people who approach it.

One of the videos he allegedly leaked was released by Wikileaks in April.

It contained footage from a 2007 attack by US forces in Baghdad in which 12 people died including two Reuters employees.

In the immediate aftermath of Mr Manning's exposure as the alleged source, reports appeared online claiming that the Pentagon was actively seeking Julian Assange.

On Monday he appeared as a panelist at a seminar on free speech held in the European Parliament and organised by the Alliance of Liberals And Democrats for Europe.

At a press conference ahead of the seminar Mr Assange spoke about the risk of action against Wikileaks by the US.

"The signals from the US authorities initially were mixed, however, they seem to clarifying now and I think the United States understands that it must obey the rule of law," he told reporters.

When asked by the BBC whether he was concerned that other people involved with Wikileaks might be vulnerable he said: "We are concerned to make sure that our volunteers in particular are protected."

We are concerned to make sure that our volunteers in particular are protected Julian Assange, Editor, Wikileaks

He added that Wikileaks would "always try and represent alleged sources".

Mr Assange said that the site had contacted three lawyers to help defend Mr Manning.

Mr Manning has to date not been formally charged, and the Pentagon has declined to comment on the case while the investigation continues.

In an e-mail sent to press and supporters last week, Julian Assange said Wikileaks planned to release another US military video showing a 2009 attack on a village in Afghanistan in which numerous civilians died.

Given the current debate over whether Mr Manning is the source of the US military videos possessed by Wikileaks, Mr Assange said he was "a little more concerned" about this release.

He added that Wikileaks would "always try and represent alleged sources".

However he was confident that Wikileaks could protect itself from any action by the US government.

Mr Assange had been heartened by a groundswell of support for Wikileaks from the online community as well as prominent journalists and politicians, he said.

"I'm sure, through their support and the integrity and correctness of what we're doing we'll be fine."