Jihadists claiming allegiance to Al-Qaeda or the Islamic State group have struck in several European countries, with France -- where there was a new attack Friday -- the hardest hit.
Here is a recap of major attacks in Europe over the past three years.
In the country's first jihadist attack, two brothers who vowed allegiance to Al-Qaeda gun down 12 people in January 2015 at the satirical weekly Charlie Hebdo in Paris.
The next day a man linked to the Islamic State (IS) group shoots and kills a policewoman in a Paris suburb. He takes hostages at a Jewish supermarket just outside Paris the following day, killing four more.
All three gunmen are killed by police.
In November 2015 France suffers its worst terror attacks when 130 people die in a string of bombings and shootings at the Bataclan concert hall and several bars and restaurants in Paris, and at the Stade de France stadium. The IS claims responsibility.
On France's July 14 national holiday in 2016 a man rams a truck into a crowd in the Mediterranean resort of Nice, killing 86 people. He is shot dead by police and the IS claims responsibility.
Also in July 2016 two teenagers linked to the IS slit the throat of an 85-year-old priest in front of worshippers at his church in the western town of Saint-Etienne-du-Rouvra
More than 240 people have been killed in such attacks in France since 2015.
In March 2017 five people die when a man rams his car into pedestrians on Westminster Bridge in London and then fatally stabs a police officer outside parliament. The attacker is shot dead by police and his actions claimed by the IS.
In May 2017 a bombing at a pop concert by US star Ariana Grande in the city of Manchester kills 22 people including children. IS extremists again claim responsibility.
In June 2017 a van rams into a crowd on London Bridge and three assailants leave the vehicle armed with knives and attack passers-by. Eight people are killed and around 50 wounded. Police shoot dead the attackers and the IS claims responsibility.
In August 2017 a 22-year-old Moroccan man mows down pedestrians with a van on Barcelona's most famous street, Las Ramblas, killing 14 people. He then goes on to kill a man from whom he steals a car.
Hours later five of his accomplices ram a car into pedestrians in the seaside town of Cambrils, 120 kilometres (75 miles) south of Barcelona. Police kill the six attackers.
IS says its "soldiers" carried out the attack.
In March 2016 suicide bombings claimed by the IS kill 32 people and injure 340 more at Brussels airport and the Maelbeek metro station, near the European Union headquarters.
In December 2016 a Tunisian man hijacks a truck and ploughs into shoppers at a Christmas market in Berlin, killing 12 people.
The attacker is shot dead by police in Milan four days later, and the rampage is claimed by the IS.
In February 2015 a gunman opens fire at a cultural centre in Copenhagen as it hosts a forum on Islam and free speech. A filmmaker is killed. Hours later another man is shot dead at the city's main synagogue.
Police later kill the gunman, who had vowed allegiance to IS.
On April 2017 a truck ploughs into shoppers outside a busy department store in central Stockholm, killing five people. Police say an Uzbek suspect who was denied a residency permit confessed.