Young Russians under the age of 18 who have led nationwide anti-government rallies in recent years are now banned from attending unauthorized protests under a newly signed law.

Russia’s youth has spearheaded anti-Kremlin demonstrations since early 2017, drawn to the streets by opposition leader Alexei Navalny and his social-media savvy team of organizers. Scores of lawmakers submitted measures criminalizing child protesters shortly after rallies against President Vladimir Putin’s inauguration in May, where authorities were seen detaining children as young as 12.

New amendments Putin signed into law Thursday impose 15 days of jail and fines of up to one million rubles ($14,400) on organizers who “involve minors” in unauthorized rallies.