The New Hampshire attorney general’s office says it is investigating what appears to be an “unlawful attempt” at voter suppression after NBC News reported on a robocall impersonating President Joe Biden that told recipients not to vote in Tuesday’s presidential primary.

“Although the voice in the robocall sounds like the voice of President Biden, this message appears to be artificially generated based on initial indications,” the attorney general’s office said in a statement. “These messages appear to be an unlawful attempt to disrupt the New Hampshire Presidential Primary Election and to suppress New Hampshire voters. New Hampshire voters should disregard the content of this message entirely.”