The National Rifle Association and several Colorado county sheriffs escalated their opposition on Thursday to a state law requiring safety training before firearm purchases, seeking to halt or narrow its enforcement. The law took effect earlier this month.

The measure requires prospective gun buyers to complete a state-approved training course before obtaining a permit to purchase certain firearms. Supporters, including Democratic Governor Jared Polis and legislative sponsors, have argued the requirement improves public safety without banning any weapons.

Several sheriffs said they lacked the staff and funding to administer the new permitting system and questioned its constitutionality. The NRA's Institute for Legislative Action signaled it would support litigation, echoing challenges the group has mounted against similar laws in other states.

Gun rights groups have pointed to the U.S. Supreme Court's Bruen decision as grounds to challenge the training mandate. State officials have defended the law as consistent with recent rulings permitting reasonable regulation.

The dispute adds Colorado to a growing list of states where post-Bruen gun laws face court battles. A spokesperson for the Colorado attorney general's office said the state was prepared to defend the statute, while county sheriffs' associations continued to press lawmakers for clearer implementation guidance and additional resources.