More than one week into Euro 2016 - some troubling gaps in security have emerged.

There have been several incidents of fans smuggling fireworks into stadiums and setting them off - including an incident with flares on friday that disrupted a game.

They threw flares on the field, and punches at each other.

A handful of Croatian fans disrupted their team's game against the Czech Republic.

Croatia's coach called them "sports terrorists."

CNN's Will Ripley reports how critics of security at the major sporting event worry terrorists could attempt to exploit these holes in security.

The month-long tournament is known to be a desired target of terror groups such as ISIS.