Twitter accounts affiliated to Islamic State have used hashtags referring to the blast to post celebratory messages, with some users encouraging similar attacks elsewhere.
Some messages described the attack as an act of revenge in response to air strikes in Iraq and Syria.
“It seems that bombs of the British airforce over children of Mosul and Raqqa has just came back to #Manchester,” one user named Abdul Haqq said on Twitter, in reference to the Iraqi and Syrian cities held by the militants where a U.S.-led coalition, of which Britain is a member, is conducting air strikes.