Two people working for a human rights body in Afghanistan were killed in a bomb attack in Kabul on June 27, the organization said.
The Afghanistan Independent Human Rights Commission (AIHRC) said the pair died when a homemade device attached to their vehicle exploded in the morning.
"It is intolerable; assassinating human rights defenders is a war crime in the context of armed conflict," the AIHRC said, adding that staff had previously been the target of attacks.
It comes less than a week after two prosecutors and three other employees from the Attorney General's Office were shot dead by gunmen on the outskirts of Kabul.
Violence had dropped across much of the country after the Taliban offered a brief cease-fire to mark the Eid al-Fitr festival last month, but officials say the insurgents have stepped up attacks in recent weeks.
The Taliban and the Afghan government are preparing to enter into much-delayed peace talks aimed at ending the war in the country.
Based on reporting by AFP and Reuters