'Authorized operator' discovered error, deleted post, Pentagon says.
The retweeted post called for Trump's resignation along with a series of politicians accused of sexual misconduct.
"The solution is simple...Roy Moore: step down from the race. Al Franken: resign from congress. Donald Trump: resign from the presidency," Proud Resister wrote in the retweeted post.
The retweet has since been deleted, but screen captures have ensured that it is not forgotten.
Pentagon spokeswoman Dana White confirmed the gaffe, saying an "authorized operator" of the Pentagon's @DeptofDefense official account "erroneously retweeted content that would not be endorsed by the Department of Defense".
The operator of the Pentagon account discovered the error and deleted it, she said.
Trump and his administration's official Twitter accounts have had a turbulent history. On the day of his inauguration, the National Park Service's official account posted photos of the assembled masses for his ceremony compared to those at former President Barack Obama's 2009 swearing-in.
The side-by-side photos depicted a crowd far thinner than was present for Obama -- debunking Trump's claim that his crowds were the largest in history and forcing a showdown with the press over the facts on the ground.