The group played a mixture of new material and classic tracks such as "Beautiful Day", ahead of Sunday's awards ceremony where U2 will pick up the "Global Icon" gong celebrating more than 40 years in the music industry.

Singer Bono wove current affairs and activism into the concert, urging fans to hold up placards they had brought to the square.

"Protesting in the end works -- it gets things done, slowly but surely," he told the crowds, who had won free tickets in a ballot organized by MTV.

Words from the US rights campaigner Martin Luther King were shown on a large screen, while Bono also talked about gender equality.

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The band played tribute to the victims of May's suicide bomb attack at a Manchester concert venue, displaying the names of the 22 people who were killed.

While the Irish frontman threw an Irish flag into the crowd, he also praised London as "the capital city of the world".

"We need each other and we have much more in common than what divides us," he said in comments addressed to London Mayor Sadiq Khan, who delivered a speech ahead of the concert.

U2's performance was followed by a set from DJ David Guetta, who will also take to the stage at the MTV awards.

Sunday's ceremony will be hosted by British singer Rita Ora and marks a return of the Europe Music Awards to London for the first time since 1996.