Concern has grown for U2 frontman Bono, who was forced to leave stage in Germany after only a few songs after his voice cut out.

The 58-year-old was performing at the Mercedes Benz Arena in Berlin on Saturday but had to stop after only five songs because he felt unable to continue.

Footage shows U2 laying the final chords of their hit song Beautiful Day, before he makes the announcement.

He starts by apologising and then says: "I promise you, before we left the dressing room, I was ready to sing for you," he said. "So something has happened, and I think we can't go on. It's not right for you."

Turning to The Edge he says: "I'm sure it's not a big big problem, but I'm going to have to do something."

He later said: "We’ll play another show for you another time." 

U2 later released a statement via their website, shedding more light on the singer’s health and assuring fans that he is seeking medical advice.

The apologetic message reads: "We’re so sorry for tonight’s cancellation. Bono was in great form and great voice prior to the show and we were all looking forward to the second night in Berlin, but after a few songs, he suffered a complete loss of voice.

"We don’t know what has happened and we’re taking medical advice. As always, we appreciate our audience’s understanding and all our fans’ support in Berlin and those who travelled from afar. We will update you very soon."

Before Beautiful Day, Bono had indicated issues to the German crowd when he said: "I think it's the smoke. I can promise you I have not been smoking. "I've lost my voice, I don't know what to do. I was singing like a bird about ten minutes ago. So I don't know what to do. I'm sure it will pass."

Bono then requested that a smoke machine was turned off before embarking on the hit song, during which he could be seen to be struggling.

The Herald:

After leaving the stage the crowd indulged in a chorus of, "how long can we sing this song", a line from the U2 song 40 taken from their album War.

This is not the first time that U2 cancelled a show mid-concert. A similar situation happened in 1989, when the band was in Amsterdam, Bono also struggled with voice problems.

They are set to play a show in Cologne, Germany, on Tuesday.

U2 are currently performing on the European leg of the Experience & Innocence tour and had already played one night at the Berlin arena.