NEW YORK (Reuters) - The National Security Agency, a U.S. electronic intelligence service, has been involved in the investigation into last year's hacker attack on Nasdaq OMX Group Inc, a U.S. enforcement official said on Wednesday.
The NSA, equipped with some of the world's most powerful computers, has been working with the Federal Bureau of Investigation and exchange officials since "suspicious files" were found on Nasdaq servers, said the official, who requested anonymity because the probe is ongoing.
The Nasdaq Stock Market parent company revealed the breach last month.
It is still unclear who was behind the attack, or what information might have been taken. Nasdaq spokesman Frank DeMaria said on Wednesday the investigation is continuing.
Last week, Securities and Exchange Commission Chairman Mary Schapiro said she wanted new rules to help protect exchanges from hackers seeking to harm U.S. capital markets. The exchanges are now mostly electronic.
Bloomberg first reported the NSA's involvement in the probe.
(Reporting by Jonathan Spicer; editing by Andre Grenon)