A suicide attack on a minibus in Kabul killed 14 foreign security guards and injured several early on Monday.
The bus was said to be carrying Nepalese security guards and was on a road to the eastern city of Jalalabad.
The attacker, who was on foot, waited for the bus as it left a compound, police said.
A Taliban spokesman claimed responsibility for the attack.
"The suicide bomber targeted a minibus of security guards of a foreign company, right now we are working to identify the nationalities of the victims," Interior Ministry spokesman Sediq Sediqqi said.
The incident follows a suicide attack on a bus near Kabul last month and an attack on a court in Ghazni in June. Both attacks were claimed by the Taliban in revenge for the execution of six prisoners.