Pharmaceutical distributors and attorneys general in 39 states are among several entities that have objected to a proposal aimed at reaching a nationwide settlement of legal claims over the opioid crisis.

The objections, filed Tuesday, potentially thwart court approval of an unprecedented idea floated by lead plaintiffs attorneys in the multidistrict litigation over opioids. Among the objectors were pharmaceutical distributors and pharmacies, which, in a combined court filing, said there were too many unknowns about the proposal, which plaintiffs attorneys amended earlier this month in an attempt to garner more support.