One Direction's Liam Payne said: "The pictures I have seen of little children in between the ruins made my heart break.
"All of us in the band are shocked by how many people need help, so we're asking the public to continue to be as generous as they possibly can."
More top news
Greater Manchester Police said "inquiries are ongoing to fully understand the circumstances of the incident."
The US president enjoyed rousing support for his political agenda as a formerly hostile audience cheered his plans in office to the rafters.
The former leader said the party needed to learn lessons after his successor Paul Nuttall failed to unseat Labour in a hard-fought campaign.