Eight Afghan policemen were poisoned and killed by their colleagues in their base in the south of the country, officials said on Saturday, in a latest so-called "insider attack".
The attack which happened in the Nawshar district of southern Zabul province late on Friday, was claimed by the Taliban, as the militants continued to escalate a deadly winter campaign of violence.
"The infiltrators first poisoned their colleagues and then shot them dead," provincial spokesman Gul Islam Seyal told AFP, adding that the attackers fled the area taking all the weapons and munitions from the base.
The governor of Zabul Bismillah Afghanmal said they had launched an investigation into the incident.
Meanwhile, Taliban spokesman Zabihullah Mujahid said in a message to the media that the group's "infiltrators" carried out the attack.
This comes just days after Afghan militants dressed as doctors stormed the country's largest military hospital, killing at least two and wounding 12 others.
So-called insider attacks - when Afghan soldiers and police turn their guns on their colleagues or on international troops - have been a major problem during the more than 15-year-long war.
Such attacks have sapped morale and caused deep mistrust within security ranks.
In a similar incident last month, an Afghan policeman linked to the Taliban shot dead 11 of his colleagues at a checkpoint in the neighbouring Helmand province.
Last September, two Afghan soldiers with suspected Taliban links killed at least 12 of their comrades as they slept in the volatile northern province of Kunduz.
The growing violence underscores rising insecurity in Afghanistan over the resurgent Taliban.
The country is bracing for an intense fighting season in the spring as the government's repeated bids to launch peace negotiations with the Taliban have failed.
Afghan forces, already beset by record casualties, desertions and non-existent "ghost soldiers" on the payrolls, have been struggling to rein in the Taliban since US-led NATO troops ended their combat mission in December 2014.