Microsoft has come out fighting after reports that Google will phase out Windows in its workplace over security concerns.

The company counterattack came after it initially declined to comment on a story in the Financial Times which cited several unnamed Google employees saying the company is dumping Windows because of worries about security.

Google has reason to fret about security. In January, Google announced that Chinese hackers had broken into its network and stolen confidential information, an incident that led the company to move its Chinese search operation to Hong Kong and out of reach of Chinese government censors. Security researchers later said hackers had targeted Google and other companies with an exploit of a then-unpatched vulnerability in Microsoft's Internet Explorer 6.

Rather than Windows, Google is offering workers the choice between Macs running Apple's Mac OS X and PCs running Linux , the Financial Times said.

"When it comes to security, even hackers admit we're doing a better job making our products more secure than anyone else," said Microsoft spokesman Brandon LeBlanc in a post on Tuesday afternoon to the company's Windows blog.

"And it's not just the hackers; third party influentials and industry leaders like Cisco tell us regularly that our [security] focus and investment continues to surpass others." LeBlanc added.

LeBlanc also ticked off half a dozen examples of Microsoft's efforts to make Windows more secure, ranging from "we ship our software and security updates to our customers as soon as possible" to " Windows 7 uses Address Space Layout Randomisation [ASLR] as well by randomising data in memory."

Security researchers, however, have questioned Microsoft's speed in patching flaws and shown how to bypass Windows' ASLR, most notably in March at the Pwn2Own hacking contest.

One industry analyst said Microsoft's response was just business as usual for the software maker.

"They'll customarily react in blogs to what they consider outrageous claims by competitors," said Rob Helm, an analyst with Directions on Microsoft. "They've done that with individual product blogs for years. The only difference is that Microsoft now has a corporate blog and an organisation to support that, which gives them a new venue to make company-level reactions."

Helm, who covers Microsoft's internal organisation, credited Frank Shaw, Microsoft's vice president of corporate communications, with pushing blogs as a response channel. Before joining the company last year, Shaw headed the Microsoft account at Waggener Edstrom, Microsoft's long-time public relations firm.

Shaw got in his shots at Google earlier Tuesday on Twitter . After calling the Financial Times story "bad reporting" in one tweet, he followed with several others, including, "news flash: Google boards up all windows in its global HQ, citing security concerns."

A security expert joined others who questioned the security rationale for abandoning Windows. "If Google is moving away from Windows, then security probably isn't the driving factor," said Andrew Storms, the director of security operations at nCircle Security. "More likely this is the public face Google wants to paint."

Google's employees already use the company's own cloud-based software, including Google Docs, said Storms, and will likely run Chrome OS when it launches later this year. That means Google won't need Windows at some point.

"If your entire company is moving to the cloud and the desktop OS doesn't matter, then why pay [Microsoft] for the licensing?" Storms said. "While you are at it, why bother with IT support systems to manage updates, backups, virus protection?"

To Storms, the move smells more like cost-cutting than security. "[But it's] been cleverly spun into a PR effort to strike at Microsoft," he said.

Microsoft and Google compete on multiple fronts, including search, where Google has a huge lead; business productivity, which Microsoft's Office dominates; browsers ; and mobile operating systems. When Chrome OS launches, they'll be direct rivals in desktop OSes as well.

Recently, some of those battles have been waged in public with dueling blog posts. Last month, for instance, Google and Microsoft traded blog punches over Microsoft's Office suite, with Google claiming that Docs was a cheaper alternative to upgrading to Office 2010; Microsoft countered that Docs can't cut it.

"It's obvious here that Google is making every effort and taking every opportunity to take shots at Microsoft," Storms said. "But based on Microsoft's mild response, it appears they aren't feeling terribly hurt."

After LeBlanc defended Windows, Microsoft again declined to comment or to provide someone from its security team for an interview. Earlier Tuesday, Google refused to confirm or deny the story, saying only that it was always looking for ways to improve business efficiency.