WikiLeaks founder Julian Assange denounced "business McCarthyism" in the United States after the Bank of America halted all transactions to the website Saturday.
The Australian, who was spending his second full day on bail, vowed the whistle-blowing site would carry on releasing controversial leaked US diplomatic cables as he insisted his life was under threat.
Bank of America, the largest US bank, halted all transactions for WikiLeaks, joining other institutions that have refused to process payments for the website since it started to publish the documents last month.
"Bank of America joins in the actions previously announced by MasterCard, PayPal, Visa Europe and others and will not process transactions of any type that we have reason to believe are intended for WikiLeaks," it said in a statement.
"This decision is based upon our reasonable belief that WikiLeaks may be engaged in activities that are, among other things, inconsistent with our internal policies for processing payments."
Assange said there was a fiscal witch-hunt against the website.
"It's a new type of business McCarthyism in the US to deprive this organisation of the funds that it needs to survive, to deprive me personally of the funds that my lawyers need to protect me against extradition to the US or to Sweden," Assange told AFP.
The term, referring to allegations of treason or subversion without proof, was coined to describe the anti-communist pursuits of former US senator Joseph McCarthy from the late 1940s to the 1950s.
Assange is staying at the mansion of journalist friend Vaughan Smith as part of his bail conditions while he fights extradition. He must also report daily to the police station in the nearby market town of Beccles, eastern England.
The 39-year-old, who had been held in a London jail before being granted bail, is wanted for questioning in Sweden over allegations that he sexually assaulted two women, which he denies.
"The case in Sweden is a travesty in the way it has been conducted. No person should be exposed to that type of investigation or persecution," he said.
"It's not performed in an open way, there are lots of underhanded dealings, giving out selected materials that we do even have.
He added: "I have seen a statement from one of the witnesses that she was bamboozled... I have heard a rumour that one has withdrawn her statement."
The former computer hacker said he fears for his safety.
"There is a threat to my life. There is a threat to my staff. There are significant risks facing us," he said.
Nonetheless, he vowed that WikiLeaks would continue releasing material.
"We are a robust organisation. During my time in solitary confinement we continued to publish everyday and its not going to change," he said.
Assange claimed earlier in an interview with Forbes magazine that a "megaleak" by the website will target a major US bank "early next year".
WikiLeaks has enraged Washington with its release of thousands of leaked US diplomatic cables and confidential military documents relating to the Iraq and Afghanistan wars.
Assange said Friday it looked "increasingly likely" the US would try to extradite him on charges related to the leaked cables as he savoured his first day on bail.
He said his lawyers believed a secret US grand jury investigation had been started into his role in the release.
Media reports suggest that US prosecutors are trying to build a case against Assange on the grounds that he encouraged a US soldier, Bradley Manning, to steal US cables from a government computer and pass them to WikiLeaks.
A report by congressional researchers said the Espionage Act and other US laws could be used to prosecute Assange, but there is no known precedent for prosecuting publishers in such a case.
US Vice President Joe Biden said that the leaks had "damaged and put into jeopardy the lives and occupations of people in other parts of the world" and made it difficult to conduct business with allies.
"For example, in my meetings -- I meet with most senior world leaders -- there is a desire now to meet with me alone, rather than have staff with me in the room. It makes things more cumbersome. So it has done damage," he said in an excerpt from interview on NBC's Meet the Press, due to air Sunday.
The latest US diplomatic cables released by WikiLeaks indicated that Sudanese President Omar al-Bashir siphoned off nine billion dollars (6.79 billion euros) of oil money into British bank accounts.
Meanwhile, according to yet another cable, the Dalai Lama, the exiled Tibetan spiritual leader, said last year the world should focus on climate change in Tibet rather than politics.