I’m certain security will be tight, even in the absence of this warning. After all, warning are part of the terrorist playbook.
Across the poster is written; ‘Russia 2018. Putin you disbeliever. You will pay the price for killing Muslims.’
The threat is likely to be linked to Putin’s support for Syrian President Bashar Al-Assad in his government’s fight against ISIS – a battle also fought by U.S.-backed Kurdish forces and other rebel factions in Syria.
In March, ISIS supporters targeted Argentinian footballer Lionel Messi in a poster showing him kneeling next to a jihadist.
http://www.dailymail.co.uk/news/article-5690359/Kill-ISIS-thugs-call-attacks-World-Cup.html