In another hit to daily fantasy sports companies like FanDuel and DraftKings, the Illinois state attorney general has declared that fantasy sports businesses are "gambling" businesses under Illinois law, and are thus operating illegally in the state.

In an opinion issued today, Attorney General Lisa Madigan writes that, under state law, it is illegal to play "games of chance or skill for money" unless the bettor themselves is participating in the game. Madigan argues that fantasy sports sites don't meet that bar, and so are currently working in violation of Illinois law.

"Absent legislation specifically exempting daily fantasy sports contests from the gambling provisions, it is my opinion that daily fantasy sports contests constitute illegal gambling under Illinois law," Madigan writes, while noting that proposed legislation in the state could exempt the sites from gambling regulation.

FanDuel and DraftKings have been waging battles on several fronts as they face tighter scrutiny from regulators. The sites were recently ordered to be shutdown in Nevada, and have been waging a legal battle in New York to continue operating in the state.