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.