Rep. Gwen Moore (D-Wis.) blamed supporters of Senate candidate Roy Moore. It wasn't immediately clear how she knew the callers backed the Alabama Republican.
After the impersonators were challenged, they "started screaming & called me & my staff the n-word," the lawmaker said in a tweet.
Earlier in the day, the congresswoman, who is black, appeared on CNN. She discussed a letter she had written to the Senate sergeant-at-arms asking what steps he would take to protect Senate pages if Roy Moore were elected.
"I won't be intimidated," she tweeted. "I won't stop speaking out."
Lauren Easton, the AP's director of media relations, said the news agency "decries any attempt to impersonate an AP journalist. AP staffers identify themselves when making calls and treat sources and interview subjects with professionalism and respect."
Moore lost Tuesday's race to Doug Jones, the first Democrat to win a Senate seat in a quarter-century in Alabama.
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