Websites like eBay and Ticketmaster are trying to shut down shameless touts selling on Manchester benefit concert tickets.
The One Love Manchester gig sold out in six minutes on Thursday morning (June 1).
But some have seen an opportunity to make a profit.
The show is being held on Sunday to raise money for the families of the victims of the Manchester Arena bombing.
Ariana Grande, who had performed on the night of the attack, will make an emotional return to the city.
Coldplay, Katy Perry and Justin Bieber are also among the stars who will playing at the Old Trafford cricket ground.
Both eBay and Ticketmaster said they were trying to remove resale listings. Other sales may be being listed through Facebook or other private sales sites.
An eBay spokesman said: “This is completely against eBay rules. We are immediately removing any listing which attempts to profit unfairly from what happened. Shoppers can give directly to Manchester via the Red Cross at checkout.”
A total of 22 people lost their lives in the atrocity. More than 100 others were injured.
Anyone who was at Ariana Grande's concert on the night of the bombing has been offered a free ticket to One Love Manchester.
Ticketmaster said: "We're working hard to get tickets direct to fans. We are cancelling tickets of those who are reselling wherever possible."
Major secondary ticketing sites Seatwave, GETMEIN, Stubhub and Viagogo have all pledged that they will not allow resales of tickets bought for the One Love Manchester benefit concert.
Also on the ever-growing bill are Miley Ray Cyrus, Pharrell Williams, Usher, Black Eyed Peas, Take That and Niall Horan from One Direction. Little Mix and Robbie Williams were announced as the latest additions today.
Ticketmaster added: “Ticketmaster was unsurprisingly met with remarkable demand for One Love Manchester tickets we had on sale this morning – 140,000 fans were on the website and our call centre was buzzing.
"With over 450,000 searches on our site for One Love Manchester over the last 24 hours, demand was always going to be extremely high.
"We are happy to report that there are thousands of fans who successfully purchased tickets during the general onsale."
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