Britain's squadron of Reaper drones is likely to be redeployed to Africa and the Middle East rather than returned to the UK, a UN official has said.

Ben Emmerson QC, the UN rapporteur monitoring counter-terrorist operations by unmanned aircraft, whose report on armed drone operations around the world will be published on Tuesday, said he believed the Ministry of Defence (MoD) had no wish to bring the drones back once the Afghan campaign ends, in December.

In an interview with the Guardian, Emmerson said he had been told the RAF's fleet of 10 Reaper drones, operated remotely via satellite from a ground station at RAF Waddington, in Lincolnshire, would remain overseas once they were withdrawn from Afghanistan.

Strict Civil Aviation Authority (CAA) rules prevent them from flying beyond the sight of the operator on the ground in UK skies, apart from inside a few restricted test areas.

Emmerson's 21-page study, for the UN's human rights council, examines targeted killings in Pakistan, Afghanistan, Yemen, Gaza and Somalia.

Among its main findings is a dramatic reduction in US drone strikes in Pakistan as control is passed from the CIA to the US defence department. It also gives details of how Israel's "knock on the roof" warnings have failed to prevent children and noncombatants being killed.

Speaking about where the UK's drones will be based, Emmerson said: "My understanding is that the plan is to deploy them to parts of Africa and the Middle East where they can be used for surveillance … over a wide range of territory [in conflicts] where one party is a jihadist group.

"The way the matter has been explained to me by senior sources close to the MoD, the current plan for the drones is Africa and the Middle East, where they can be quickly deployed into situations of tension."

The drones could be based in countries such as Nigeria or Djibouti, he suggested. "I would be surprised if they were not thinking about returnees from Syria so they can monitor the axis of jihadist violence," he said.

Emmerson – whose full title is UN rapporteur on the promotion and protection of human rights and fundamental freedoms while countering terrorism – visited central Africa in the aftermath of the French intervention against jihadist groups in Mali.

"There were no armed drones used in the conflict in Mali," he said. "That was considered [by military officials] a severe deficiency in capabilities. The French didn't have any and the US didn't have any armed ones. "

The MoD said no decisions on redeploying the RAF's drones had yet been taken. A spokesman said: "At present, there are no plans to deploy UK unmanned air systems anywhere other than Afghanistan. Decisions about future basing of these assets, once operations in Afghanistan conclude, are likely to be taken later this year."

But Emmerson's comments dovetail with other indications that UK drones may be sent to the Arabian peninsula. During a visit to RAF Waddington in December the defence secretary, Philip Hammond, was asked whether Reapers could be redeployed against al-Qaida supporters in Yemen. He replied: "We have to pursue the terrorists wherever they take themselves … Wherever there's an ungoverned space, there's a risk."

International concern over the impact of armed drones is growing. Last month, the European Union parliament passed a motion condemning their use "outside the international legal framework", and called for a common EU position.

Emmerson's report is expected to trigger a debate in the UN's human rights council in Geneva. The submission contains a draft resolution calling for independent investigation of strikes where civilians have been killed, and for countries using remotely piloted aircraft for "lethal counter-terrorism operations" to clarify their legal position.

Pakistan is increasingly critical of US drone strikes on the Taliban in its north-west frontier provinces, warning that the attacks are counter-productive. The rapporteur's document notes that no drone strikes have been reported in Pakistan since Christmas 2014, "the longest pause since Obama took office".

That cessation had coincided, he said, with control of US drone strikes being passed from the intelligence services to the military.

Emmerson added: "The Pakistan government needs to be given the space to develop their peace strategy. I was told in June last year, by counter-terrorist officials and the director of the CIA, that the process of migrating drone strategy to the US department of defence was under way."

The rapporteur said Pakistan had not given consent to US strikes. "Whatever co-operation there may still be at intelligence level," he told the Guardian, "none of that makes a difference when, as a matter of international law, Pakistan does not consent to armed drones in its territories. Statements by the Pakistan government are strongly opposed to use of drones."

Emmerson has obtained access to senior officials controlling drone policy. As well as meeting the director of the CIA, MoD executives in London and Israeli representatives, he has travelled to Pakistan, South America and central Africa; he has not yet succeeded in getting into Yemen.

While the number of drone attacks has been declining in Pakistan, they have been increasing in Afghanistan and Yemen. Last year, drone strikes accounted for 40% of civilian fatalities inflicted by aerial attacks in Afghanistan, according to UN figures.

The report highlights Israel's practice of giving advance warning of drone strikes by leafleting local populations and sending text messages urging them to leave the area if they are noncombatants.

In some cases, unarmed missiles are dropped on a building – the so-called knock on roof – five minutes before the explosive charge is delivered.

"If you don't get out, your are presumed to be a combatant," Emmerson said. "One child was killed by a dropped warning. [The Israelis] maintain that if [people] don't leave they are acting as 'voluntary human shields'."

He added: "These weapons are for counter-insurgency operations. We are going to see an increase in drone [strikes], year on year. They should be confined to combatants. It's crucial that we have agreement about who is a combatant.

"Some of the theories out there would allow states to target or kill individuals who are in close proximity to fighters on the basis of collateral damage or [their being] voluntary human shields. Getting these rules agreed is critical."

States such as the UK, which are involved in intelligence-sharing with other countries should also be careful to agree ground rules in case information could be used for targeted killings, he said.