BEIJING – China vowed Tuesday to keep a tight grip on the Internet, saying it would continue to block anything considered subversive or threatening to “national unity.”

The “white paper” statement of government policy was released three months after a public dispute over censorship prompted Google Inc. to shut its mainland-based search engine.

It said there were 384 million Internet users in China at the end of 2009, about 29 percent of the population. The government aims to boost that to 45 percent in the next five years by pushing into rural areas where the white paper said there was a “digital gap.”

It said the Internet had taken an “irreplaceable role in accelerating the development of the national economy” and would continue to impact daily work, education and lifestyles.

But China, which routinely blocks websites such as Facebook, YouTube and Twitter, gave no sign there would be an easing of the “Great Firewall” — the nickname for the network of filters that keep mainland Web surfers from accessing material the government deems sensitive.

The official English translation of the white paper favorably mentions Twitter — an apparent glitch since the U.S. microblogging service has been banned in China since last year. The English version named Twitter as an example of a fast-growing service that allows people to express themselves, while the Chinese version mentions only micro-blogs.