They claim that the information attack is conducted through bots on the social network VKontakte and in instant messengers.
The reason was the fact that companies did not transfer to Russia servers with personal data of Russian users.
The exhibition was to be held from February 24 to 27 in Barcelona.
The application is the second largest service after the social network Facebook.
“We have evidence that Huawei has the capability secretly to access sensitive and personal information in systems it maintains and sells,” Robert O’Brien said.
Pages used by the Iranian, Myanmar and Vietnamese authorities were also blocked for violating social network’s policy.
The reason is that they did not provide information on meeting the requirements for localizing the databases of domestic users on servers situated in Russia.
The top five list also includes singer Ariana Grande, actor Dwayne Johnson, singer Selena Gomez and media personality Kylie Jenner.
“Since January 24, the Protonmail.com mail service (Switzerland) was used by anonymous users to continue criminal activity,” the FSB statement says.
The portal Engadget reported that the Czech company sells its customers’ data to such entities as Google, Home Depot, Microsoft and Pepsi.