Gunmen shot dead nine Afghan aid workers, including one woman, in the country's northern Balkh province on Tuesday.
Afghan officials said they all worked for the Czech-backed aid group People in Need, which announced the suspension of all operations in Afghanistan after the attack.
Government officials blamed the Taliban, but the group has not yet claimed responsibility.
Afghan officials said a World Food Programme (WFP) convoy was also attacked in a different region but rescued by police, adding six attackers were killed during the clash and one was detained.
As many as 57 aid workers, mostly Afghan employees, were killed last year, the United Nations says.
Meanwhile, government officials say Taliban and ISIS militants have been fighting in the western province of Farah for the last couple of days, which caused a heavy toll on both sides.
The heavy fighting started after ISIS fighters demanded Taliban militants swear allegiance to their leader Abu Bakr al-Baghdadi, Anadolu Agency reported.
According to the report, at least 27 militants from both sides have died during the recent fighting between two groups, including an ISIS commander. Another ISIS commander and 11 fighters were captured by the Taliban, as the Afghan air force conducted several raids against the militants.
Officials said Afghan ground soldiers have not join the battle in Farah, which is a strategically important province bordering Helmand province to the east and Iran to the west.