Radio 1's Big Weekend has held a minute's silence at the event to remember victims of the Manchester bombing.
The two-day festival kicked-off with an increased police presence following the atrocity at Manchester Arena.
Picture special: Stars wow the Hull crowds on the first afternoon of Radio 1s Big Weekend
Before singer Zara Larsson opened the festival on the main stage, the event tweeted: "There will be a minute's silence at Radio 1's Big Weekend at 3pm - to remember our fellow music lovers who died in Manchester."
Larsson dedicated a song, Symphony, to victims of the attack.
She told the crowd: "Music itself, it doesn't have a religion, it doesn't have a country, or an ethnicity, it's something that we do and it unites us all.
"I want this song to be dedicated to what happened in Manchester. It's about wanting to be a part of someone's symphony, someone's life. That to me is the most beautiful thing."
The two-day festival, which has been hit by some rain, will see 50,000 music fans gather at Burton Constable Hall near Hull to see acts including Katy Perry, Kings Of Leon, Bastille, Lorde, Kasabian and Little Mix.
Ben Cooper, Radio 1's controller, promised that extra measures would be taken in the wake of Monday's bombing following Ariana Grande's show, which killed 22 and injuring dozens of others.
Mr Cooper told the Press Association that the safety of the artists, audiences and those working at Radio 1's event has been their "absolute priority".
He said organisers will be conducting two rounds of thorough searches for those entering the venue, and that dogs will be used.
Humberside Police has confirmed it will up its support, but that this may not mean festival-goers will see a military presence.
Grande's London O2 Arena gigs on Thursday and Friday were cancelled and the London premieres for Wonder Woman and The Mummy next week have also been pulled.
Saturday night will see pop star Perry headline the stage, while Sunday's headliner is Kings Of Leon.
Dan Reynolds, frontman of Imagine Dragons, who are on the bill, told the Press Association: "It's been a really sad, tragic week and felt across the world, especially in the music community.
"But the music industry is also standing up and saying no individual is going to stop music and put fear into the hearts of any of us. Music will continue.
"All we can do is love more, accept more and continue to play music because that is the greatest binding fear that can exist.
"My mom called me and tried to convince me not to come here but that (terror attacks) can happen anywhere in the world.
"I'd never live in fear and give that power to some other individual to make me not do what I love."
Fans said that seeing the police presence and the extra bag checks made them feel "secure" and was "comforting".
Radio 1 DJ Nick Grimshaw took to the stage to introduce the minute's silence following a set by James Arthur.
Grimshaw told the crowd: "I thought we could take a minute to talk about Manchester and the events of Monday night.
"Like you guys, all of us at Radio 1 have been thinking about Manchester all week and we've been completely heartbroken and we thought it would be nice if we could take a minute's silence for everyone who lost their lives in Manchester on Monday."
His voice cracking, he added: "After that we're going to make as much noise as we can, to defiantly make a really loud noise as a community of music lovers, to show that we are here for everyone affected by that."