An international website that claims to blow the whistle on corporate and governmental fraud vowed yesterday to defy attempts by a US court to close it down. Wikileaks allows whistleblowers to anonymously post documents in an attempt to expose corruption and wrongdoing. Its owners said yesterday that a Californian judge had ordered that the site be taken offline last week, after an injunction from a Swiss bank.

The bank, Julius Baer, sought the injunction to prevent claims being posted online that it was involved in money laundering and tax evasion in the Cayman Islands. It has indicated that the information was prejudicial to an ongoing court case.

Last night, the version of the site hosted in the US remained unavailable, but duplicate sites hosted in India and Belgium were still accessible.

Information on the Wikileaks site led to a front-page Guardian story in August 2007, exposing money laundering in Kenya by former president Daniel Arap Moi, and in November the site published a confidential briefing memo from Northern Rock that was picked up by the Guardian, the Financial Times and the BBC.

The site published hundreds of pages of information from a former bank employee about the offshore activity of Julius Baer. Several documents allegedly relate to money laundering claims. The bank could not be reached for comment yesterday.

Last week a Californian district court judge, Jeffrey White, accepted the bank's injunction without amendment and also ordered Dynadot, the site's domain registry, to delete all record of the address from the central internet domain registry. Wikileaks' founders said the US court's move breached the first amendment.