Physicists from both New Zealand and Britain have been credited with splitting the atom — but there is consensus that it was not an American.

U.S. President Donald Trump's declaration in an inauguration speech that Americans “split the atom” prompted vexed social media posts on Tuesday by New Zealanders, who said the achievement belonged to a pioneering scientist revered in his homeland.

After President Trump's claim, a mayor in New Zealand pointed out that work to split the atom was actually pioneered by physicist Ernest Rutherford.

Nick Smith, the mayor of Nelson, challenged Trump’s claim Americans split the atom, stating the feat was actually achieved by New Zealand physicist Ernest Rutherford.