Morgan Stanley experienced a very sensitive break-in to its network by the same China-based hackers who attacked Google Inc's computers more than a year ago, Bloomberg reported, citing leaked emails from an Internet security company.

The emails from the Sacramento, California-based computer security firm HBGary Inc said that Morgan Stanley -- the first financial institution identified in the series of attacks -- considered details of the intrusion a closely guarded secret, the report said.

Bloomberg quoted Phil Wallisch, a senior security engineer at HBGary, as saying that he read an internal Morgan Stanley report detailing the so-called Aurora attacks.

The HBGary emails don't indicate what information may have been stolen from Morgan Stanley's databanks or which of the world's largest merger adviser's multinational operations were targeted, according to the report.

Representatives for HBGary were not immediately available for comment.

A Morgan Stanley spokeswoman declined to comment on whether the bank had been targeted in the Aurora attacks.

Morgan Stanley invests significantly in IT security and manages a robust program to deal with malware and attempted computer compromises, spokeswoman Sandra Hernandez said in a statement emailed to Reuters.

Chinese Foreign Ministry spokeswoman Jiang Yu repeated that China opposed any kind of hacking.

We often hear this kind of story. I don't know if related parties have reported this to the relevant authorities asking China to cooperate, Jiang told a regular news briefing.

We ... will use the law to go after any kind of hacking or crime on the Internet, she added.

(Reporting by Soyoung Kim and Yinka Adegoke in New York, Noel Randewich in San Francisco and Ben Blanchard in Beijing; Editing by Jon Loades-Carter)