The weekend attacks were the worst perpetrated on Danish soil in decades.

Danes have been vigilant of terror threats since Aarhus-based Jyllands-Posten in 2005 published 12 cartoons of the prophet, sparking protests across the Muslim world.

Danish police have said they averted several alleged terror plots in recent years, including plans for a series of bombings in Copenhagen in 2007.

The Danish Embassy in Pakistan was hit by a suspected suicide bomber in 2008. And another terror plot to attack offices was foiled in 2010.