The Taliban warned Wednesday of reprisals if the Afghan government executes any of its militants in an expected series of hangings.

Kabul hanged eight criminals on Tuesday and officials said more executions were expected after President Hamid Karzai signed death warrants for a total of 16 prisoners.

The Taliban, who are waging an insurgency against Karzai's government and 100,000 NATO troops, said they had "credible reports" that some Taliban members on death row were scheduled for execution.

If the "prisoners of war" were executed there would be "heavy repercussions for lawmakers, courts and other related circles of the Kabul administration", the Islamists said in a statement on their website.

It urged the United Nations, the Organisation of the Islamic Conference, the Red Cross and international rights groups to prevent the executions.

The Taliban, ousted from power by a US-led invasion in 2001, were notorious for executing people in public for "crimes" including adultery. The executions were often carried out at half-time during games in the main football stadium in Kabul.

The European Union and international rights groups on Wednesday condemned Afghanistan's execution of the first eight prisoners and urged Kabul to drop plans to hang any more.

"The Afghan government should end its sudden surge of executions and institute a moratorium on further executions," Human Rights Watch said.

"The weakness of the Afghan legal system and the routine failure of courts to meet international fair trial standards make Afghanistan's use of the death penalty especially troubling," it said.

Amnesty International said "the sheer number of people who could be killed by the state is a particularly shocking use of what is the ultimate cruel and inhuman form of punishment".

The EU mission in Afghanistan called on the government to commute all death sentences and to reintroduce a moratorium on executions as a first step towards abolishing capital punishment.