The family and friends of two Iraqi activists disappeared in Baghdad this week have said they fear more will vanish, as the United Nations warned security forces and unknown militias had unleashed a campaign of abductions and “deliberate killings”.

Activist Salman Khairallah Salman and his friend Omar al-Amri were last seen on Wednesday morning heading to Baghdad’s Kadhimiya district. There they had hoped to buy tents for an encampment in the capital’s Tahrir Square, the hub of the protest movement.

But both stopped answering calls by 10.30am, and by 2.30pm their mobile phones had been switched off.

Their disappearances are just the latest in a slew of abductions, which Amnesty said on Friday were part of a “campaign of terror” against protesters.

The UN assistance mission in Iraq (Unami) meanwhile said on Wednesday it had credible evidence that thousands of demonstrators have been arrested and held incommunicado, or abducted by “unknown armed men”.

Mr Amri’s family told The Independent they believe the two activists were arrested by the security forces and are being held at Baghdad’s al-Muthana airport detention facility for interrogation.

Iraq protests: Death toll soars as live rounds and tear gasfire Show all 17 1 /17 Iraq protests: Death toll soars as live rounds and tear gasfire Iraq protests: Death toll soars as live rounds and tear gasfire Iraqi protesters take cover behind a barricade on Al-Jumhuriya Bridge during an anti-government demonstration in the Iraqi capital Baghdad on 25 October, 2019. AFP/Getty Iraq protests: Death toll soars as live rounds and tear gasfire Protesters push down concrete walls during a protest over corruption, lack of jobs, and poor services, in Baghdad. Reuters Iraq protests: Death toll soars as live rounds and tear gasfire Anti-government protesters try to break into the provincial council building during a demonstration in Basra. AP Iraq protests: Death toll soars as live rounds and tear gasfire Iraqi women protesters march with national flags during an anti-government demonstration in the central holy shrine city of Najaf. AFP/Getty Iraq protests: Death toll soars as live rounds and tear gasfire An Iraqi protester uses a mobile phone to take a selfie photo with an army soldier standing atop a humvee during a demonstration outside the local government headquarters in the southern city of Basra. AFP/Getty Iraq protests: Death toll soars as live rounds and tear gasfire Iraqi protesters gather during an anti-government demonstration at the burning local government headquarters in Nasiriyah, the capital of Iraq's southern province of Dhi Qar. AFP/Getty Iraq protests: Death toll soars as live rounds and tear gasfire Iraqi protesters wave a national flag as they stand atop the gatehouse to the local government headquarters in the southern city of Basra. AFP/Getty Iraq protests: Death toll soars as live rounds and tear gasfire An Iraqi protester throws back a tear gas canister fired by security forces amid clashes during an anti-government demonstration in Baghdad. AFP/Getty Iraq protests: Death toll soars as live rounds and tear gasfire Iraqi protesters carry away an injured protester following clashes during an anti-government demonstration in Baghdad. AFP/Getty Iraq protests: Death toll soars as live rounds and tear gasfire Iraqi security forces stand guard on Al-Jumhuriya Bridge during an anti-government demonstration in Baghdad. AFP/Getty Iraq protests: Death toll soars as live rounds and tear gasfire Anti-government protesters gather in Tahrir Square during a demonstration in central Baghdad. AP Iraq protests: Death toll soars as live rounds and tear gasfire The burning local government headquarters in Nasiriyah, the capital of Iraq's southern province of Dhi Qar. AFP/Getty Iraq protests: Death toll soars as live rounds and tear gasfire Protesters take cover behind a concrete barricade during a demonstration in Baghdad. AFP/Getty Iraq protests: Death toll soars as live rounds and tear gasfire Iraqi paramedics help injured protesters in Baghdad. AFP/Getty Iraq protests: Death toll soars as live rounds and tear gasfire Iraqi protesters gather in Baghdad. AFP/Getty Iraq protests: Death toll soars as live rounds and tear gasfire An Iraqi protester takes cover between concrete barricades in Baghdad. AFP/Getty Iraq protests: Death toll soars as live rounds and tear gasfire Protesters take cover from teargas canisters fired by security forces in Baghdad. AFP/Getty

“We continue the search for Omar and check the police station every day. We have filed a missing person report but so far nothing and it’s been two days,” the brother, who asked not to be named, said.

Distressed, he added: “It’s hard to describe how we feel right now. We are extremely worried this will happen to more people and about the whole situation.”

Mustafa Mauyad, a friend of both missing activists, said many protesters now fear for their lives.

“We heard in the days leading up to the abduction, security forces had begun questioning tent sellers in the district where they vanished about people purchasing tents for the protests,” he said.

“The family are extremely scared. I feel like I’m facing a real threat, like I could be next.”

It is not known how many people have gone missing since the protests first erupted on 1 October against political corruption that is rife in the country.

More than 440 people, mostly unarmed protesters but also some members of the security forces, have been killed since that date, according to a Reuters tally.

Protesters blame Iran-backed militia groups for a spate of other killings including assassinations.

Paramilitary groups have denied any role in attacking protests. Government security forces also deny using live ammunition against peaceful protesters.

The surge in violence has also seen a string disturbing acts of bloodshed being carried out by unknown groups.

On Thursday, a teenage boy was killed and strung up by his feet from a traffic pole in Baghdad after he allegedly shot protesters.

Videos circulating on social media show the young man being beaten and dragged across the street, while security forces stand by.

In other footage, dozens of people are seen filming and photographing the mutilated body which dangles high above them in a central Baghdad square.

It followed the killing of 25 protesters last week in Baghdad’s Khilani Square by gunmen in pick in up trucks. That same week, mysterious knife attacks targeted more than a dozen anti-government protesters in Tahrir Square, the hub of the protest movement.

There are conflicting reports as to what exactly happened on Thursday, but Iraqi security officials said an enraged mob beat to death a 16-year-old boy after he opened fire in Baghdad’s Wathba Square, killing two shop owners and four protesters.

But activists told The Independent he was actually killed by security forces who handed the body to the mob who then stabbed him multiple times and strung up the corpse.

Jeanine Hennis-Plasschaert, Unami’s chief, warned the “gang-driven” acts of violence risk placed the country “in a dangerous trajectory”.

In an Unami report released on Wednesday, they identified at least five high-profile activists who have been abducted like Mr Amri and Mr Salman recently.

A man weeps by the coffin of an Iraqi protester and citizen journalist, who was killed during a demonstrations the previous day in Baghdad (AFP/Getty) (HAIDAR HAMDANI/AFP via Getty Images)

The report urged the government to identify those groups responsible without delay and hold perpetrators accountable.

“Demonstrators and activists may be being targeted based on social media posts and their degree of influence or following,” the report stated.

“Bearing the primary responsibility for the protection of its people, the state must spare no effort to protect the peaceful protesters from violence by armed actors operating outside state control, as well as those with formal and informal reporting lines within the state,” it added.

Amnesty meanwhile has documented instances of assassination attempts against protesters, the deployment of snipers, the use of military-grade skull-shattering tear gas canisters and “a pattern of disappearances and abductions”.

The state must spare no effort to protect the peaceful protesters from violence UN Assistance Mission in Iraq (Unami)

It said apart from the abductions in Baghdad a number of activists had also been disappeared in Karbala around the same time.

It urged the Iraqi authorities to stop “the relentless campaign of intimidation against protesters”.

“The international community must urgently speak up and address the alarming situation in Iraq, as it takes a new dangerous turn and risks escalating further,” said Lynn Maalouf, Amnesty International’s Middle East research director.