The anti-secrecy group WikiLeaks says its website is under attack.

The group said on its twitter feed Tuesday its main site was brought down by a cyber-attack, but it provided a link where it said visitors could still search through its trove of leaked U.S. diplomatic cables. In a second message a few minutes later, the group provided a link for a so-called “mirror” site at which the main page could also be viewed.

The attack comes just hours after the U.S. State Department criticized WikiLeaks' latest mass release of leaked diplomatic cables, saying it is a serious threat to individuals named in the documents and to U.S. national security.

State Department spokeswoman Victoria Nuland said Tuesday the publication of the cables also undermines U.S. diplomatic efforts to, in her words, “solve shared problems.”

WikiLeaks in the past week has published on its website more than 125,000 State Department cables. Before this, it had made public about 20,000 such documents. According to several news outlets, these newly-released cables contain the names of a number of sources who had asked for protection and for their identities not to be released.

In its Twitter feed, WikiLeaks denied that it had exposed any sources. The twitter message said the New York Times, which was among the first newspapers to report WikiLeaks had identified protected individuals, was “drooling, senile, and evil.”