Human Rights Watch said the near-simultaneous disappearance of four activists in Pakistan raised concerns of government involvement. The US-based watchdog said the four men had been critical of both militant groups like the Taliban as well as the Pakistani military establishment.

Salman Haider, a poet and academic, and bloggers Waqas Goraya, Aasim Saeed, and Ahmad Raza Naseer - who campaigned for human rights and religious freedom - went missing from various Pakistani cities between January 4 and 7.

Hundreds of people attended protests in Pakistan's major cities Tuesday (pictured above), calling for the bloggers' immediate recovery.

Government complicit?

Brad Adams, Asia director at Human Rights Watch (HRW), said that the Pakistani government had "an immediate obligation to locate the four missing human rights activists and act to ensure their safety," adding that anything short of this would make the government look complicit in their disappearance:

"The nature of these apparent abductions puts the (...) government on notice that it can either be part of the solution or it will be held responsible for its role in the problem," Adams said.

Weekend disappearances

The HRW statement said the four had disappeared on the same weekend. Haider was last seen in the capital Islamabad on Friday.

Over the weekend, Pakistan's interior ministry said it had ordered an investigation into the possible kidnapping of Haider; it is unclear whether any investigations are underway in the cases of the other three men.

Pakistan's independent Human Rights Commission has also expressed concern, demanding the men be located.

No group has claimed responsibility for abducting any of the four individuals. And, authorities have not posted any information to indicate that they might have been detained.

Liberal groups throughout the country announced they would hold protests in reaction to the disappearances, using the social media hashtag #RecoverAllActivists.

Pakistan: a scary place for journalists

Pakistan is ranked among the world's most dangerous countries in the world, not only for journalists. The Global Travel and Tourism Report published by the World Economic Forum ranks Pakistan as the fourth most dangerous place in the world.

Journalists critical of Pakistan's powerful military and the country's opaque security policies have in the past been detained, beaten and even killed. Many find themselves caught between the country's security establishment and militant groups - including the Taliban.

In April 2015, prominent activist Sabeen Mahmud was killed by militants who said they attacked her because she promoted liberal, secular views.

In April 2014, gunmen attacked Hamid Mir, one of the country's most recognized TV anchors. The presenter, who survived that attack, has also tweeted in favor of recovering missing academic Salman Haider.

Government complicit?

Hamid Mir's family and employers have accused Pakistan's powerful intelligence service, the Inter-Services Intelligence agency (ISI) of being behind the attempt on his life.

The ISI has been regarded as complicit in several such cases before; political assassinations have shaped the history of the nation.

Newspaper airs suspicion

Pakistan's leading English-language daily newspaper "Dawn" meanwhile said in a strongly-worded editorial that "the state of Pakistan continues to be suspected of involvement in the disappearance and illegal detentions of a range of private citizens."

"It is simply not enough for government and police officials to claim that the disappearances are being investigated. Mr Haider and the other recently missing activists need to be returned to their families immediately," the statement added.

ss/ipj (AP, AFP, epd)