British police raided a property in the Manchester district of Fallowfield where they carried out a controlled explosion on Tuesday (May 23).
The raid followed a suicide bombing that killed 22 people, including children, in an attack on a crowded concert hall.
Manchester remained on high alert, with additional armed police drafted in.
The suspected attacker was named as Salman Abedi, aged 22.
Two United States officials who have been in contact with British authorities said he was believed to have travelled to Manchester from London by train.
Monday’s attack was the deadliest in Britain since four British Muslims killed 52 people in suicide bombings on London’s transport system in 2005.
Attacks in cities including Paris, Nice, Brussels, St. Petersburg, Berlin and London have shocked Europeans already anxious over security challenges from mass immigration and pockets of domestic Islamist radicalism. Islamic State has repeatedly called for attacks as retaliation for Western involvement in the conflicts in Syria and Iraq.
