The International Monetary Fund has said it is investigating a sophisticated cyber attack on its computer system.
Officials gave few details but said the attack had been "a very major breach" of its systems. Concerns about the attack were great enough that the World Bank cut a computer link that allows the two organisations to share non-sensitive information,
IMF spokesman David Hawley said the organisation is fully functional but declined to provide further details. Mr Hawley would not reveal the scope or nature of the attack and whether any sensitive data were taken.
The New York Times cited unnamed IMF officials as describing the attack as "sophisticated and serious". The IMF told staff about it on Wednesday but hasn't made a public announcement.
Already facing a public-relations headache after the arrest of Dominique Strauss-Kahn, who resigned as IMF chief last month after being accused of sexually assaulting a maid in a New York hotel, the attack has come as a blow to the fund which holds sensitive and confidential financial data on countries around the world.
It's not clear what the nature of the attack was or if the hackers were in fact targeting the IMF. Nor is it clear if the attack was politically motivated or not. Hackers sometimes try to distribute malicious software code widely and see which organisations it can infect.
But they can also choose targets. Using a technique called "spear phishing," for instance, they can trick employees of a specific organisation into clicking a link that then gives hackers access to its computer systems.
It's possible the IMF was the victim of such hacktivism. However, the New York Times report said the attack occurred over the last several months, before Strauss-Kahn was arrested.
The IMF attack follows a series of major data breaches at major companies.
In recent months, hackers have penetrated 100 million Sony PlayStation accounts, the networks of Lockheed Martin and the customer email databases of a company that does marketing for Best Buy and Target stores. Google has accused Chinese hackers of targeting the Gmail accounts of US government officials. About 200,000 Citibank credit card customers in North America had their names, account numbers and email addresses stolen.