Vietnam’s prime minister posted a letter online on Thursday urging the public to use the Internet responsibly and build a civilised web environment, in rare comments promoting cyberspace in a country renowned for crushing dissent.

In a letter more than 1,100 words long posted on the government’s website and its new Facebook page, Nguyen Tan Dung said the Internet was key to transparency and “contributes to the assurance of freedom, human rights and civil rights”. While Internet usage and smartphone sales have soared in Vietnam, its communist government has dealt harshly with its online critics, with rights groups angered by the arrests, intimidation and jailing of dozens of bloggers and activists. Reporters Without Borders has previously dubbed Vietnam an “enemy of the Internet” for its suppression of online dissidents.

Dung, whose government has been credited with steering a series of liberal reforms to the economy to court more investors, is one of only a few among Vietnam’s leaders to have advocated the use of Facebook.

The ruling Communist Party has until recently steered clear of a platform used by more than a third of its 90 million population. “We saw clear risk of abusing Internet to disperse information that is fabricated, unverified, without reliable source, toxic and offensive that aims to slander and smear individuals, organisations and brands, spreading ideas and organising terrorism, vandalism,” Dung said.

His letter mentioned big international tech names as familiar to Vietnamese such as Google, Facebook, YouTube, Twitter, Viber and some local news websites.

At a ministerial meeting last year, Dung asked officials to be more active on social networks, which have become one of the prime sources of information in his country. Vietnam has 49 percent of its population on the Internet, higher than the world’s average of 40.4 percent and the Asia-Pacific region mean of 32.4 percent, the letter said.