Intel Corp said it faced a sophisticated hacker attack in January about the same time as the recently publicized Chinese hacker attacks on Google Inc, but noted no clear link between the two events.

Google would not comment on whether Intel was one of the roughly 20 unnamed companies that the world's No. 1 Internet search engine said had been similarly targeted in attacks that originated in China.

The attack was just one of what the world's largest chipmakers said were regular attempts on its computer systems, Intel said in a filing under a heading about potential theft or misuse of the company's intellectual property.

The only connection is timing, Intel spokesman Chuck Mulloy said, declining to elaborate. The company first publicized the attack and pointed out the similarity in timing to the move on Google in an annual filing with the U.S. Securities and Exchange Commission.

Now that Google has publicly admitted to being successfully attacked without much damage to their reputation, analysts said other companies are rethinking their typically tight-lipped approach to security breaches.

Recent changes to disclosure laws and increased awareness of cyber-security may also have prompted Intel to come clean, analysts say.

But Intel did not say who was behind the attacks, from where in the world they originated, or what information, if any, had been taken.

Asked whether Intel had spoken or worked with Google on this issue, Mulloy said: Our security folks work very closely and collaboratively throughout the industry.

Companies are facing these threats and attacks all the time, Fred Pinkett, vice president of product management for Core Security Technologies, said.

In targeting companies like Intel, which have one of the largest intellectual property portfolios in the world, hackers may have been looking for bragging rights.

Very rarely are they really trying to commit industrial espionage, because it's really hard to do that without getting caught, said Todd Feinman, chief executive of Identity Finder.

The reason Intel probably publicized the hack attempts was to minimize the company's legal risks, he added. The advantage is that you're protecting yourself for when it finally does happen and something really bad occurs, because you can say 'we disclosed this information on our 10-K.'

Intel shares closed down 48 cents, or 2.31 percent, at $20.38 on Nasdaq. They edged up to $20.40 after hours.

(Reporting by Ian Sherr; Additional reporting by Alexei Oreskovic; Editing by Lisa Von Ahn, Gerald E. McCormick and Richard Chang)