National Security Agency officials deliberately overstepped their legal authority multiple times in the past decade, the agency acknowledged on Friday.

The admission contradicts previous statements by lawmakers and the Obama administration that any privacy violations were unintentional.

“Over the past decade, very rare instances of willful violations of NSA’s authorities have been found, but none under [the Foreign Intelligence Surveillance Act] or the Patriot Act,” the agency said in a statement. “NSA takes very seriously allegations of misconduct, and cooperates fully with any investigations – responding as appropriate. NSA has zero tolerance for willful violations of the agency’s authorities.”