A new independent study places Pakistan among the top four countries, including Brazil, Mexico and Syria, where people have been murdered in each of the last three years for writing about sensitive subjects online.
The annual "Freedom on the Net" report, released Tuesday by U.S.-based Freedom House, is based on an assessment of internet freedom in 65 countries, accounting for 87 percent of internet users worldwide. The latest study primarily focused on developments between June 2016 and May 2017.
The research declared Pakistan "not free" for a sixth consecutive year, noting internet freedom has deteriorated due to violence and intimidation related to social media activists.
"Internet shutdowns, a problematic cybercrime law, and cyberattacks against government critics contributed to the ongoing deterioration. Political speech online is vulnerable to restriction as Pakistan enters an election year in 2018," the report noted.
The most frequent targets, it says, seem to be online journalists and bloggers covering politics, corruption and crime, as well as people who express religious views that may contrast with or challenge the views of the majority.
The study went on to conclude that perpetrators of the reprisal attacks remained unknown "but their actions often aligned with the interests of politically powerful individuals or entities."
The report documented incidents of violence and intimidation during the research period. The government of Pakistan has not commented on the findings.
In June, a Pakistani court sentenced to death earlier this year an internet user, Taimoor Raza, for committing blasphemy on Facebook. In April, university student Mashal Khan was killed in the northwestern Khyber Pakhtunkhwa province by a mob who accused him of posting blasphemous content online.
Khan's murder sparked widespread outrage across Pakistan. An anti-terrorism court is hearing the lynching case against 57 suspects indicated by the court.
"Such attacks often succeed in silencing more than just the victim, encouraging wider self-censorship on sensitive issues like religion. The state's failure to punish perpetrators of reprisal attacks for online speech perpetuates a cycle of impunity," according to the report.
The Pakistani government enacted the Prevention of Electronic Crimes Act in August 2016, introducing stronger censorship and surveillance powers with inadequate oversight, say critics.
Earlier this year, five bloggers known for criticizing the powerful military and religious militancy were abducted for few weeks. One of them later told media a government institution had detained and tortured him. Authorities had distanced themselves from the alleged abductions.
Tuesday's report also criticized the government for the prolonged suspension of mobile internet services in parts of Pakistan, including the violence-plagued northwestern federally administered tribal areas, where security forces have been conducting anti-militancy operations.