A woman arrested in the UK on suspicion of involvement in the Manchester suicide attack has been released without charge, but six other men remain in custody in England and Libya with authorities fearing a second attack may be imminent.
British-born Salman Abedi, 22, who was known to security services, killed 22 people and injured 64 others at the Manchester Arena which was packed with children and teenagers for US singer Ariana Grande's performance on Monday night.
Authorities believe he had help in building the bomb, which photographs published by the New York Times, showed was sophisticated and powerful, and that his accomplices could be ready to strike again.
After the attack Manchester police raided a number of properties across northern and central England arresting five men and one woman on Wednesday, but the woman was later released without charge, Manchester Police said.