Rockers U2 have hired a security team to guard their dressing rooms during their new tour -- because fans kept nicking mementoes from their backstage compound.

They were so fed-up with items going missing during their last tour they have put beefed-up security measures in place for their first gig in Barcelona later this month.

The measures include drafting in 50 guards, installing CCTV and watch towers to keep an eye on band members' private rooms.

Only their closest friends and family will get anywhere near the band with just 10 Access All Areas passes being handed out for each gig.

U2 are currently rehearsing for their huge stadium tour which kicks off at the Nou Camp on June 30. A group insider said: "The security arrangements around this tour are the most extreme we have ever seen. It is ultra-strict. The security operation will be the biggest ever mounted for a rock tour.

"The problem is during the last tour a few fans even managed to sneak in during concerts and they ended up running off with the band's clothes and possessions."

The group's 360 Degree tour will hit Croke Park in July for three 90,000 capacity concerts.

Inside the stadium there will be five levels of security with different passes for each.

To get into the final zone -- which allows direct access to the band -- lucky VIPs will have to pass a series of security points and undergo a body scan with metal detectors.

While Bono and the group are performing CCTV cameras will monitor the halls leading to their rooms and the whole compound will become a "lock down."

The source added: "It means there won't be a free for all while they are singing."