Vietnam's president called on Sunday for tougher controls on the internet in the face of dissidents who are using it to criticize the ruling Communist Party, and to combat threats to cybersecurity.
Vietnam's government has stepped up a crackdown on activists this year, but despite the arrest and sentencing of several high-profile figures, there has been little sign of it silencing criticism on social media.
President Tran Dai Quang made the call in an article published on the government website.
He said hostile forces had used the internet to organize offensive campaigns that "undermined the prestige of the leaders of the party and the state, with a negative impact on cadres, party members and people."
Quang said Vietnam needed to pay greater attention to controlling online information, especially on social networks, and needed an effective solution "to prevent news sites and blogs with bad and dangerous content."
Quang's own standing had been the subject of internet rumor and gossip in recent days because he has been largely absent from the public eye.
Vietnam has intensified crackdowns on both government critics and officials accused of corruption since security-minded conservatives gained greater sway within the Communist Party early last year.
Vietnam is in the top 10 countries for Facebook users by numbers and Google's YouTube is also a popular platform.
Quang also highlighted threats to cybersecurity, saying Vietnam was under increasing attack by criminals seeking information and state secrets, and attempting to carry out acts of sabotage.
Thousands of computers in Vietnam were affected by the WannaCry virus in May.
In a report three months ago, security company FireEye said hackers working on behalf of the Vietnamese government had broken into the computers of multinationals in the country.
Vietnam forcefully rejected the accusation.