A lawyer representing the founder of WikiLeaks, Julian Assange, says he will discuss with UK police a European arrest warrant from Sweden related to sexual assault allegations guardian.co.uk

Julian Assange, the founder of WikiLeaks, is expected to appear in a UK court today after his lawyers said he would meet police to discuss a European arrest warrant from Sweden relating to alleged sexual assaults.

As the legal net continued to close around the whistleblowers' website and the US attorney general, Eric Holder, said he had authorised "a number of things to be done" to combat the organisation, Assange appeared to be reconciling himself to a lengthy personal court battle to avoid extradition to Sweden.

Jennifer Robinson, a solicitor with Finers Stephens Innocent, which represents the Australian freedom of information campaigner, told the Guardian: "We have a received an arrest warrant [related to claims in Sweden]. We are negotiating a meeting with police."

Another lawyer representing Assange, Mark Stephens, added: "He has not been charged with anything. We are in the process of making arrangements to meet the police by consent, in order to facilitate the taking of that question and answer that is needed. It's about time we got to the end of the day and we got some truth, justice and rule of law."

Stephens explained that the interview would happen in the "foreseeable future" but he could not give a precise time. According to other sources, it is thought that Assange would appear before a court to negotiate bail .

Assange is seeking supporters to put up surety and bail for him. He said he expected to have to post bail of between £100,000 and £200,000 and would require up to six people offering surety, or risked being held on remand.

In recent days, Assange, 39, has told friends he is increasingly convinced the US is behind Swedish prosecutors' attempts to extradite him for questioning on the assault allegations.

He has said the original allegations against him were motivated by "personal issues" but that Sweden had subsequently behaved as "a cipher" for the US.

Assange has also said that he declined to return to Sweden to face prosecutors because he feared he would not receive a fair trial, and prosecutors had requested that he be held in solitary confinement and incommunicado.

This weekend Assange said he was exhausted by the effort of running his defence against the allegations in Sweden and the release of the US embassy cables at the same time, as well as running WikiLeaks itself, which has split since some supporters became disaffected over Assange's handling of the Afghanistan war logs. Once he turns himself in to the police, he will have to appear before a magistrates' court within 24 hours, where he will seek release on bail. A full hearing of his extradition case would have to be heard within 28 days.

In the past, Assange has dismissed the allegations, stating on Twitter: "The charges are without basis and their issue at this moment is deeply disturbing."

Last week Stephens added: "This appears to be a persecution and a prosecution. It is highly irregular and unusual for the Swedish authorities to issue [an Interpol] red notice in the teeth of the undisputed fact that Mr Assange has agreed to meet voluntarily to answer the prosecutor's questions."

Stephens has said that the claims stem from a "dispute over consensual but unprotected sex". While the latest US diplomatic cables released on WikiLeaks have been stirring international political alarm and recriminations, Assange is understood to have been staying out of public sight in south-east England.

Prosecutors in Sweden issued a warrant for his arrest last month but it could not be enforced because of a technical blunder. The Australian's details were also added to Interpol's most wanted website after a red notice was issued, alerting police worldwide to his status.

Detectives in Sweden want to question Assange after two women claimed they were sexually assaulted by him when he visited the country in August. The country's supreme court upheld an order to detain him for questioning after he appealed against two lower court rulings.

The sex assault claims may be Assange's most pressing legal issue, but it may not be the only legal complication he faces as several countries consider the impact of his diplomatic cable disclosures.

He has come under growing pressure after WikiLeaks started publishing excerpts from a cache of 250,000 secret messages.

In the US, the level of political vituperation has become more vengeful. The former vice-presidential candidate Sarah Palin has described Assange as "an anti-American operative with blood on his hands". The senior Republican Mike Huckabee said that "anything less than execution is too kind a penalty".

Meanwhile WikiLeaks has been forced to move to a Swiss host after being dumped by US internet companies as it comes under siege from cyber attacks.

PostFinance, the financial arm of the Swiss post office, said it had closed Assange's account after he provided "false information".

"PostFinance has ended its business relationship with WikiLeaks founder Julian Paul Assange," the bank said in a statement. "The Australian citizen provided false information regarding his place of residence during the account opening process."

Last night hackers claimed they had targeted the firm's websites in support of WikiLeaks.

MasterCard also said it would block payments to WikiLeaks, according to the CNET News website, a move that will dry up another source of funds for the website.

"MasterCard is taking action to ensure that WikiLeaks can no longer accept MasterCard-branded products," a spokesman for MasterCard Worldwide said yesterday.

The credit card firm said it was cutting off payments because WikiLeaks was engaging in "illegal activity". "MasterCard rules prohibit customers from directly or indirectly engaging in or facilitating any action that is illegal," its spokesman, Chris Monteiro said. The online credit firm PayPal has already refused to allow payments through for WikiLeaks.

In Sweden, a WikiLeaks spokesman called for action against those who have attacked Assange. "There have been death threats to his life and incitement to murder," he added.

Canadian newspapers reported that police are investigating whether there is evidence to proceed against a former adviser to the prime minister after he called for Assange to be killed.

Tom Flanagan, now a professor at the University of Calgary, suggested on television last week that Assange "should be assassinated, actually", adding: "I think Obama should put out a contract and maybe use a drone or something."

Flanagan later retracted his statement saying it was not meant seriously.

In Assange's homeland, however, Australian police are investigating whether he has broken any laws.