Pakistani journalist Gul Bukhari, who has openly criticised the military, was briefly abducted by masked men in Lahore.

The brief abduction of a prominent Pakistani social activist and newspaper columnist known for her strident criticism of the country’s powerful military has raised fears of a renewed crackdown on dissent in the South Asian country.

Gul Bukhari, 52, was abducted by several unidentified men while she was on her way to a television news studio in the eastern city of Lahore on Tuesday night, a family member told Al Jazeera.

Several hours later, she was released, they confirmed, although they did not provide any details regarding the attack.

The abduction has heightened fears among activists and journalists, coming as it does in the wake of widespread censorship of news considered critical of the military and certain political parties, and prompted concern that a new wave of intimidation is imminent.

Bukhari, who is a vocal critic of the military and its alleged role in censoring Pakistan’s media and involving itself in political processes, was abducted a day after the military warned that it was monitoring social media activity for “anti-state, anti-Pakistan and anti-army” material.

“We do have the capability to monitor social media, to see who is doing what,” said Major-General Asif Ghafoor, the military’s spokesperson, on Monday.

In a separate incident on Tuesday, journalist Asad Kharal was also assaulted in Lahore by “some persons wearing masks,” he said.

Pakistan ranks 139 out of 180 countries on Reporters Without Borders’ World Press Freedom Index, and attacks against journalists and other media professionals – particularly those deemed critical of the state – are common.

Since last year, the state has carried out a sustained campaign targeting those critical of the military – which has ruled Pakistan for roughly half of its 70-year history – on social media, an Al Jazeera investigation found.

‘There is no stopping them’

The attack on Bukhari comes as the distribution of Dawn, Pakistan’s oldest and most respected daily newspaper, was disrupted in several areas across the country, a source told Al Jazeera, allegedly over its publication of an interview with former Prime Minister Nawaz Sharif that implied military complicity in the 2008 Mumbai attacks.

In April, the Geo News television station, one of the country’s most popular news networks, came back on air after weeks of being blocked by cable operators, also allegedly at the behest of the military.

Geo was allowed to resume transmissions only after it agreed to a deal with the military to change its editorial stance on certain political issues, two officials at the channel told the Reuters news agency.

Earlier this year, several newspaper columnists were told that their regular op-ed columns, most on the subject of the Pashtun Tahaffuz Movement (PTM) rights group, would not be published. The PTM has held countrywide rallies against alleged rights abuses by the military in the country’s northwest since January.

“It appears that those behind this abduction want to send a message to the rest of Pakistan and the world that they can do whatever they want, whenever they want, to dissenters, and that there is no stopping them,” said Taha Siddiqui, a journalist who was forced to flee the country after a similar abduction attempt in January

“The Pakistan army cannot tolerate dissent, and they have managed to control the mainstream Pakistani media. Now they are desperately trying to do the same with social media.”

Siddiqui now runs SAFE Newsrooms a whistleblowing website that encourages South Asian journalists to report censorship within their newsrooms anonymously. The site was blocked by the Pakistani government within weeks of being launched.

Pakistan’s military denies that it has issued any directives to media organisations to control their coverage, inviting news organisations to report on the alleged censorship if it has taken place.

“Whenever I have spoken to [media owners and journalists], I have said the same thing: right now Pakistan needs to unite, to present its successes and build on them,” said General Ghafoor on Monday. “That is what I told them we need to do, and that is what they have done.”

Asad Hashim is Al Jazeera’s Digital Correspondent in Pakistan. He tweets @AsadHashim.