SAN FRANCISCO – Google’s privacy practices are the worst among the Internet’s top destinations, according to a watchdog group seeking to intensify the recent focus on how the online search leader handles personal information about its users.

In a report released Saturday, London-based Privacy International assigned Google its lowest possible grade. The category is reserved for companies with “comprehensive consumer surveillance and entrenched hostility to privacy.”

None of the 22 other surveyed companies – a group that included Yahoo, Microsoft and AOL – sunk to that level, according to Privacy International.

While a number of other Internet companies have troubling policies, none comes as close to Google to “achieving status as an endemic threat to privacy,” Privacy International said in an explanation of its findings.

In a statement from one of its lawyers, Google said it aggressively protects its users’ privacy and stands behind its track record.

“We are disappointed with Privacy International’s report, which is based on numerous inaccuracies and misunderstandings about our services,” said Nicole Wong, Google’s deputy general counsel.

Privacy International contacted Google earlier this month but didn’t receive a response, said Simon Davies, the group’s director.

The scathing report is just the latest strike aimed at Google’s privacy practices.

The company says it stockpiles data to help its search engine better understand its users so it can deliver more relevant results and advertisements.

As Google becomes more knowledgeable about the people relying on its search engine and other free services, management hopes to develop more tools that recommend activities and other pursuits that might appeal to individual users.

Privacy International is particularly troubled by Google’s ability to match data gathered by its search engine with information collected from other services such as e-mail, instant messaging and maps.

“Under the microscope, it turns out that Google is doing much more with our data than we ever imagined,” Davies said.

Founded in 1990, Privacy International said it reached its preliminary findings after spending the past six months reviewing Internet privacy practices with the help of about 30 professors, mostly in the United States and United Kingdom. The group plans to update the report in September.