The UN has said there are "credible allegations" of more than 100 extrajudicial killings in Afghanistan since the Taliban took power in August, with most blamed on the country's new rulers.

UN deputy rights chief Nada Al Nashif said on Tuesday she was deeply alarmed by continuing reports of such killings, despite a general amnesty announced by the Taliban after their August 15 takeover.

"Between August and November, we received credible allegations of more than 100 killings of former Afghan national security forces and others associated with the former government," she told the UN Human Rights Council.

"At least 72 of these killings," she said, were "attributed to the Taliban".

"In several cases, the bodies were publicly displayed. This has exacerbated fear among this sizeable category of the population," she said.

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'Brutal methods' on suspected Daesh-K members

Taliban Foreign Ministry spokesperson Abdul Qahar Balkhi said the government was "fully committed" to the amnesty decree, and denied employees of the previous administration were being persecuted.

Anyone "found breaching the amnesty decree will be prosecuted and penalised", he said.

"Incidents will be thoroughly investigated but unsubstantiated rumours should not be taken at face value."

Nashif, who presented Tuesday's update to the council on behalf of UN rights chief Michelle Bachelet, said many members of the Daesh-Khorasan group – a main Taliban enemy – had also been killed.

"In Nangarhar province alone, there... appears to be a pattern of at least 50 extrajudicial killings of individuals suspected to be members of the DAESH-K," she said, with reports of "brutal methods... including hanging, beheadings, and public display of corpses".

READ MORE:Afghanistan’s Taliban and Daesh: A simmering rivalry

Amnesty report

In a report released on Wednesday, Amnesty International also said members of the Taliban had tortured and killed ethnic and religious minorities, former Afghan soldiers and suspected government sympathisers as they seized control of Afghanistan in July and August.

"Our new evidence shows that, far from the seamless transition of power that the Taliban claimed happened, the people of Afghanistan have once again paid with their lives," said Amnesty Secretary General Agnes Callamard.

Amnesty said the full scale of the killings remained unknown.

The UN and Amnesty comments came after the United States and other countries condemned the Taliban following a Human Rights Watch report earlier this month documenting 47 summary executions.

Those killings were of former members of the Afghan National Security Forces, other military personnel, police and intelligence agents "who had surrendered to or were apprehended by Taliban forces" from mid-August through October, it said.

Taliban spokesperson Qari Sayed Khosti flatly rejected the HRW report and other claims about extrajudicial killings as "not based on evidence".

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