Fresno State University in California says an American history professor who tweeted that President Donald Trump "must hang" will not be returning to teach in the fall.

University President Joseph Castro said in a statement Friday that professor Lars Maischak wouldn't be teaching when classes resume.

But he says two of his courses would be converted to an online format to fulfill a contractual obligation.

Castro says Maischak's contractual assignment concludes in December.

Maischak had taken a voluntary leave of absence after apologizing for the tweet he wrote in April.

It said: "To save American democracy, Trump must hang. The sooner and the higher, the better."