Afghanistan on Wednesday executed six "criminals and terrorists", an official said, a day after eight other death row prisoners were hanged.
The Taliban, which is leading an insurgency against the Western-backed government, has warned there would be reprisals if any of their militants were executed.
President Hamid Karzai approved the executions of the six who were sentenced to death "on charges of terror, conducting attacks, explosions and organising suicide attacks", a government spokesman said in a statement.
The Taliban, who are fighting Karzai's government and 100,000 NATO troops, said if what they called "prisoners of war" were executed there would be "heavy repercussions" for government officials.
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 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.