A teenage suicide bomber attacked a performance at the French Cultural Center in Kabul on Thursday, killing at least one person.
France's Foreign Minister Laurent Fabius said "several" people died in the blast, though none of the victims was French. A senior Afghan official identified one of the dead as a German citizen.
Afghan authorities believe the bomber was around 16 years old and had hidden explosives in his clothes before entering the crowded auditorium on the grounds of the French-financed Istiqlal High School.
In a deadly day for the capital, the Taliban claimed responsibility earlier Thursday for a bus bombing that killed six soldiers.
Dozens of people were injured in the two explosions.
Militants have been stepping up attacks, particularly in Kabul, hitting both Afghan security forces and foreign troops as well as diplomatic targets.
NATO forces are ending their combat mission in Afghanistan after 13 years and transitioning to a new mission in January focusing on training and advising Afghan troops.