Section 12. Whoever knowingly resists or obstructs the commissioner, any local superintendent or employee or authorized agent of any of them, while any of those persons is engaged in suppressing or eradicating the Asian longhorned beetle, oak wilt or any public nuisance described in section 11, or whoever knowingly violates any rule, regulation, order or quarantine issued by the commissioner, in writing, relative to the suppression or eradication of public nuisances shall be subject to a civil penalty of not more than $25,000 for each violation. Each day that such violation occurs or continues shall be deemed a separate violation. The penalty may be assessed by the department, and may be recovered in an action brought on behalf of the commonwealth in the superior court. The commonwealth also may bring an action for injunctive relief in the superior court for any such violation, and the superior court shall have jurisdiction to enjoin such violation and to grant such further relief as it may deem appropriate.