Manchester comes amid 300 terror deaths in EU

The 22 people who died at the Ariana Grande concert in Manchester are the latest victims in a wave of attacks that has swept Europe and killed at least 302 people since 2015, all at the hand of Islamist extremists.

The blast on Monday night was the deadliest terrorist attack in the United Kingdom since the July 7, 2005 bombings in London that left 52 people dead.

The bomber was identified as Salman Abedi, 22, who was born in Britain of Libyan parents. Fears that he was part of a cell of extremists prompted UK authorities to raise its terrorism threat level to critical, meaning that another attack is thought imminent. Soldiers have been deployed at some key locations as a temporary measure.

Police detained Abedi's brother in Manchester on Tuesday and arrested a further three on Wednesday.

The weapons used in recent attacks include vehicles, knives, guns and explosives and the perpetrators in the vast majority of recent outrages have been extremists who have directly or indirectly supported either the Islamic State or al-Qaida.

The deadly assault in Manchester came just two months after a lone attacker plowed a car into pedestrians on Westminster Bridge in London, killing four and injuring over 50, before crashing into the fence surrounding the Houses of Parliament and stabbing a police officer to death before being shot and killed by police.

In December, a Tunisian man drove a stolen truck through a crowded Christmas market in Berlin, killing 11 people. The terrorist had previously killed the truck driver.

That attack was similar to one in Nice, in the south of France, on July 14, 2016, that saw a Tunisian-born French citizen kill 84 people by driving a rented truck into a crowd of revelers celebrating Bastille Day, France's national day.

Earlier last year, 32 people were killed by three suicide bombings in Brussels. Two bombs exploded at the city's main international airport and one at a subway station in the center of the city. The killers were all Belgian nationals.

In November 2015, a series of attacks in Paris claimed the lives of 130 people. In that attack, gunmen and suicide bombers targeted the Bataclan concert hall, a major stadium, and restaurants and bars. Most of the attackers had French or Belgian citizenship and two were Iraqis.

Paris was still in shock after the January 2015 attack on the Charlie Hebdo satirical newspaper's office by two French gunmen. That attack and subsequent violence left 17 people dead.

The total of 302 dead in recent attacks does not include smaller acts of violence, such as the killing of two Muslim men in Britain in separate incidents in 2016 or two killings by right-wing extremists. During recent years, European police and civilians have foiled scores of terrorist conspiracies.