The boyband - who found fame on 'The X Factor' 2010 - has added extra security members to their team to deal with their eager Canadian fans.
As source told the Daily Star: "Fans kept mobbing them. They came back from Niagara Falls and thousands of baying girls were throwing themselves at the tour bus."
The group which consists of Harry Styles, Louis Tomlinson, Liam Payne, Zayn Malik and Niall Horan have had massive problems with staying safe recently.
Louis was woken by a naked man trying to get into his hotel room in Stockholm, Sweden recently.
It turned out the nude man was not a fan trying to get close to Louis but was simply trying to find a toilet.
But the real scare came after two members were mobbed in New York.
Liam and Niall Horan were attacked by a gang of 60 screaming girls outside their hotel, with Liam having his t-shirt ripped and Niall having his hair pulled last Sunday.
A source said: "It was crazy. As they left the hotel on 54th Street this sea of girls engulfed them. Their security was desperately trying to keep them safe but they were completely surrounded."