Rock band U2 have criticised US politicians including Hillary Clinton for using their shows to raise funds.
U2 are playing stadium gigs in America as part of the Vertigo tour
The band were angered after Democrat Ms Clinton gave supporters a chance to be in her suite at the band's Washington concert in return for a party donation.
Republican senator Rick Santorum is making a similar offer for U2's Philadelphia show.
"U2 concerts are categorically not fundraisers for any politician," said a band spokesman.
He added: "They are rock concerts for U2 fans."
New York senator Ms Clinton is offering the chance for 18 people to join her in a luxury suite at Washington's MCI Center when U2 play the venue on 19 October.
Supporters have to contribute $2,500 (£1,430) to the Democratic Party to get a place.
The former first lady's spokeswoman said: "We do a meet-and-greet with the senator, and then go in and listen to music."
Pennsylvania senator Mr Santorum is holding a similar event at the Philadelphia show this Sunday with places costing $1,000 (£572) per person.
U2 have been involved in political activity themselves, backing campaigns against nuclear testing and nuclear power, while singer Bono has campaigned to help the financial and health crisis in Africa.