A top US intelligence official warned football fans travelling to Russia for the World Cup that their phones and computers could be hacked by Moscow’s cyber spies.

William Evanina, Director of the National Counterintelligence and Security Center, said that in Russia, even people who believe they are too unimportant to be hacked can be targeted.

“Anyone travelling to Russia to attend the World Cup should be clear-eyed about the cyber risks involved,” Evanina said in a statement.

“If you’re planning on taking a mobile phone, laptop, PDA, or other electronic devices with you — make no mistake — any data on those devices (especially your personally identifiable information) may be accessed by the Russian government or cybercriminals.”

Evanina, in charge of the agency that assesses and counters the threat to the Untied States from foreign espionage, said that people attending the World Cup, which begins on Thursday, should leave behind any devices they can do without.

For devices they take with them, they should remove the battery when it is not in use, he said.

“Corporate and government officials are most at risk, but don’t assume you’re too insignificant to be targeted.”