Attorney General Jeff Sessions says Colorado isn’t making good on its promises to stop marijuana from spilling over its borders, nor is the state keeping it out of the hands of kids.

Sessions raised “serious questions” about the state’s marijuana regulation and called on Gov. John Hickenlooper to remedy the situation in a letter obtained by The Cannabist. It is dated July 24 and arrived at the Colorado Capitol late Thursday, officials said.

The governors of at least two other states that have legalized adult-use cannabis also received letters from the attorney general addressing the efficacy of their respective state marijuana regulatory structures.