US concert booking website Ticketmaster was hit by a cyberattack last year that led to it botching sales for Taylor Swift's US tour, it told lawmakers on Tuesday as it apologized to the pop superstar and her fans.

Critics have long accused the company of being a monopoly, but fan outrage boiled over in November as website outages left thousands of "Swifties" who had been hoping to catch the 33-year-old "Bad Blood" singer's Eras tour empty-handed.

Joe Berchtold, the president of parent company Live Nation, told the Senate Judiciary Committee the meltdown came after the website was "hit with three times the amount of bot traffic than we had ever experienced."

"While the bots failed to penetrate our systems or acquire any tickets, the attack required us to slow down and even pause our sales," he said.

Ticketmaster immediately became a focus of Swifty fury, while members of Congress accused it of anti-competitive practices and called for curbs on its dominance -- or even for the company to be broken up.

Apologizing to the 11-time Grammy Award-winner and her fans, Berchtold told senators an "ever-escalating arms race" had sprung up between ticketing companies and "industrial scalpers, using bots and cyberattacks" to illegally obtain tickets for resale.

"In hindsight, there are several things we could have done better. And let me be clear that Ticketmaster accepts its responsibility as being the first line of defense in spots in our industry as ever-escalating arms race," he testified.

The cyberattack disclosure did not take the heat off of the company, however.

Witnesses also included outspoken Ticketmaster critic and musician Clyde Lawrence -- whose band "Lawrence" included the line "Live Nation is a monopoly" in its 2021 song "False Alarms."

'800-pound gorilla'

He said Live Nation's triple role owning the venue, financing the show and selling the tickets for gigs gave it outsized power when negotiating with artists.

"If they want to take 10 percent of the revenues and call it a facility fee, they can, and have. If they want to charge $30,000 for (rent], they can and have. If they want to charge us $250 for a stack of clean towels, they can, and have," he said.

Democratic Senator Richard Blumenthal offered Live Nation a tongue-in-cheek congratulations for uniting both sides of the political divide on the issue.

"May I suggest, respectfully, that unfortunately your approach today in this hearing is going to solidify that cooperation," he said, accusing the company of blaming "everyone but us" for its shortcomings, despite being "the 800-pound gorilla here."

Government estimates put Ticketmaster's market share as high as 80 percent, although the company says the figure is closer to 60 percent.

Live Nation denies monopoly allegations and said in a November statement it "does not engage in behaviors that could justify antitrust litigation, let alone orders that would require it to alter fundamental business practices."

Swift was not in the US Capitol as senators grilled the witnesses, but a handful of her fans gathered in front of the building to denounce the platform's actions.

Ticketmaster is "controlling the industry in a way that makes it completely unfair to consumers," said Jennifer Kinder, 56, an attorney from Dallas who represents Swift fans.

"We're really hopeful with this hearing... Swifty fans are not going away until Ticketmaster is changed."

© Agence France-Presse