It's the third major attack in Europe in just a few days.
Munich in southern Germany was the scene of the latest shooting.
Nine people were killed in a crowded shopping centre before the 18-year-old gunman shot himself dead.
The motive of the German student of Iranian origin remains unclear.
The Islamic State of Iraq and the Levant (ISIL, also known as ISIS) has quickly taken credit for other recent attacks.
Detectives in Munich say the shooting was not a "terrorist" act, but it exposes yet again the enormous security challenges across Europe and elsewhere.
Inside Story discusses why some Western media quickly point the finger at groups such as ISIL.
Presenter: Dareen Abughaida
Philipp Rotmann, Associate Director of the Global Public Policy Institute.
Habib Battah, Editor-in-Chief of the Beirut Report.
Source: Al Jazeera