A grenade was thrown at a vehicle belonging to United Nations in the Afghan capital Kabul on Sunday, killing a foreign national and wounding five others, a government spokesman said.
Nasrat Rahimi, the interior ministry spokesman, did not give the nationality of the deceased.
Five Afghans, including two United Nations local staff, were slightly wounded in the attack.
No group has claimed responsibility, Reuters reported.
The attack took place after a week's lull in the heavily fortified capital following a series of bomb attacks in recent months.
Both Taliban and ISIS are active in the capital and have repeatedly claimed previous attacks.
Meanwhile, a statement released by United Nations Assistance Mission in Afghanistan (UNAMA) on Sunday condemned the attack, and called on the Afghan authorities to make swift investigations.
For his part, UN Secretary-General António Guterres, called on the authorities to “spare no effort in identifying and swiftly bringing to justice” those responsible.