The Swiss Post Office bank closed an account set up by WikiLeaks founder Julian Assange, saying he gave "false information" after claiming to have lost 100,000 euros in a financial clampdown this week.
The bank, PostFinance, said in a statement that it had "ended its business relationship with WikiLeaks founder Julian Paul Assange."
"The Australian citizen provided false information regarding his place of residence during the account-opening process."
Assange had given an address in the Swiss city of Geneva as his residence, it added.
Wikileaks retorted in a Twitter message that the Swiss bank had frozen 31,000 euros ($41,700) of "Julian Assange's defence fund and personal assets."
"The technicality used to seize the defence fund was that Mr Assange, as a homeless refugee attempting to gain residency in Switzerland, had used his lawyer's address in Geneva for the bank's correspondence," it added.
WikiLeaks advertised the PostFinance account details online to "donate directly to the Julian Assange and other WikiLeaks Staff Defence Fund," giving an account name of "Assange Julian Paul, Geneve."
The closure marked a new setback for the WikiLeaks frontman, amid intense pressure to close the whistleblowing website since it began releasing highly sensitive US state department cables.
US-based online payment service PayPal on Friday, blocked financial transfers to WikiLeaks after governments around the world initiated legal action against the website.
That froze 60,000 euros, according to the site.
"WikiLeaks and Julian have lost 100,000 euros in assets this week," it claimed.
PostFinance spokesman Alex Josty declined to say whether there was money in the Swiss account, but he underlined that it would belong to the Australian.
"He would have a right to that money and we would ask him where to transfer it," Mr Josty said.
PostFinance revealed over the weekend that it was in the process of carrying out checks after it failed to find Assange's name registered in Geneva.
"Assange entered Geneva as his domicile. Upon inspection, this information was found to be incorrect," it concluded on Monday.
"Assange cannot provide proof of residence in Switzerland and thus does not meet the criteria for a customer relationship with PostFinance. For this reason, PostFinance is entitled to close his account."
The bank had said that checks would normally involve correspondence with Mr Assange, who is currently in hiding and faces an international arrest warrant issued by Swedish prosecutors on sex assault allegations.
However, his case turned out to be more difficult.
"We haven't had contact with him and we don't know where he is," Mr Josty explained.
PostFinance said accounts are normally granted to Swiss residents or foreigners from areas nearby.
But for people from more distant countries, like Australia or the United States, they must have some kind of relationship with Switzerland, such as business ties or a house.
Despite Swiss banking secrecy, under money-laundering laws and due diligence requirements for banks, clients must give their real domicile.
PostFinance has said the checks were made because of Mr Assange's growing media exposure, making him a high-profile client under due diligence requirements.