One Direction fans spark security fears

British boyband One Direction are sparking mass hysteria in America – prompting their management to ramp up security.

The group – comprising Niall Horan, Zayn Malik, Liam Payne, Harry Styles and Louis Tomlinson – shot to fame after coming third in the 2010 season of the UK version of X Factor.

They have being making waves in the US with their debut album Up All Night. The record recently claimed the number one spot on iTunes in the country.

One Direction have encountered overzealous fans as a result of their newfound fame.

Niall was reportedly mobbed as he attempted to take photos in Times Square in New York City.

The 18-year-old had to return to the band's hotel, which was also surrounded by hordes of female admirers.

"Fans were crying and shaking when they caught a glimpse of the band," a witness told British newspaper Metro. "It was very surreal. Others were banging on the glass of the windows and hotel managers were worried they would smash the glass."

Meanwhile, Justin Bieber has taken to his Twitter page to congratulate One Direction on their recent success.

The pop heartthrob also praised British band The Wanted who are currently riding high in the charts too.

"congrats to my dudes @onedirection for the #1 album on itunes and @thewantedmusic for the #2 on singles. We share the same queen. #Canadian (sic)," he posted, before adding: "good guys always win bro. congrats," in response to Niall's thank you.

Katy Perry has also tweeted her support.

The songstress was a guest judge on The X Factor when Niall was put through to boot camp stages.

"congratulations, you didn't let me down! Xo," she wrote, before Niall replied: "hey katy, thank you, let's hope it holds out this week! Thank you for putting me thru! we've been working hard,I won't let you down (sic)"