An activist of the Resistant Citizen, against the junta-backed constitution seals her mouth with duct tape and holds a placard reading "7 Reasons To Not Accept Constitution" during gathered to hold activities against the draft constitution, ahead of the August 7 referendum in front of the Election Commission Office in Bangkok, Thailand, June 15, 2016. REUTERS/Chaiwat Subprasom

BANGKOK (Reuters) - Two 8-year-old girls in Thailand have been charged for violating campaigning rules ahead of a contentious referendum next month after tearing voter lists off a wall because they liked the pink paper they were printed on, police said on Sunday.

The military government has clamped down on dissent ahead of the Aug. 7 vote on a military-backed constitution that it says will ensure stability in a country rocked by political turmoil for more than a decade.

The girls were charged with obstructing the referendum process and destroying public property after tearing down the lists posted outside a school, said Damrong Phetpong, police commander in the northern province of Kamphaeng Phet.

“They confessed to tearing down the voter lists because they liked the color pink,” Damrong told Reuters.

He said they would not face punishment because they were so young.

The referendum will be the first big test of the public’s opinion of the military government since it came to power after a May 2014 coup.

Critics, including major political parties, say the draft charter would give the military too much power over elected governments, and would not resolve differences between populist political forces and the military-dominated establishment.

The government, which appears increasingly jittery ahead of the vote, has brought in a law banning discussion of the constitution and lobbying, both for and against, with a 10-year prison sentence for anyone who breaks it.