British soldiers arrive by bus and head toward a building next to New Scotland Yard police headquarters near to the Houses of Parliament. Pic/ AFP

Soldiers were being deployed to key sites in Britain on Wednesday to prevent attacks after the terror threat level was raised to its highest level following a suicide bombing in Manchester that killed 22 people, including children. Prime Minister Theresa May announced late on Tuesday that the threat level was now considered "critical", meaning an attack may be imminent. Police had earlier named British-born Salman Abedi, 22, as the perpetrator of the bombing at the Manchester Arena indoor venue at the end of a concert by U.S. pop singer Ariana Grande on Monday, attended by thousands of children and teenagers. The identities of the victims were becoming known little by little. They included an eight-year-old girl, two teenage girls and a 28-year-old man. A Polish couple who had come to collect their daughters after the concert also died, Poland's foreign minister said. The daughters were safe.