Here are some past notable extremist attacks in Western Europe:
January 7, 2015: A gun assault on the Paris offices of satirical magazine Charlie Hebdo killed 12 people. Al-Qaeda in the Arabian Peninsula claimed responsibility for the attack, saying it was revenge for Charlie Hebdo’s cartoons considered blasphemous to Islam.
May 24, 2014: Four people were killed at the Jewish Museum in Brussels by an intruder with a Kalashnikov. The accused is a former French fighter linked to the Islamic State group in Syria.
May 22, 2013: Two al-Qaeda inspired extremists ran down British soldier Lee Rigby in a London street, then stabbed and hacked him to death.
March 2012: A gunman claiming links to al-Qaeda killed three Jewish schoolchildren, a rabbi and three paratroopers in Toulouse, southern France.
July 22, 2011: Anti-Muslim extremist Anders Behring Breivik planted a bomb in Oslo then attacked a youth camp on Norway’s Utoya island, killing 77 people, many of them teenagers.
November 2, 2011: Offices of Charlie Hebdo in Paris were firebombed after the satirical magazine ran a cover featuring cartoons considered blasphemous to Islam. No one was injured.
July 7, 2005: 52 commuters were killed when four al Qaeda-inspired suicide bombers blow themselves up on three London subway trains and a bus.
March 11, 2004: Bombs on rush-hour trains killed 191 at Madrid’s Atocha station in Europe’s worst terror attack.
August 15, 1998: A car bomb planted by an Irish Republican Army splinter group killed 29 people in the town of Omagh, the deadliest single bombing of Northern Ireland’s four-decade conflict.
July 25, 1995: A bomb at the Saint-Michel subway station in Paris killed eight people and injured about 150. It was one of a series of bombings claimed by Algeria’s GIA, or Armed Islamic Group.