Muhammad Ali aimed a powerful message at Republican presidential candidate Donald Trump on Wednesday, saying the recent global terrorism crisis has “perverted people’s views on what Islam really is.”

Ali became a Muslim and changed his name from Cassius Clay during the height of his career as one of the greatest boxers in history.

His message came in a statement after a week in which Trump cast doubt on President Obama’s assertion that several American “sporting heroes” practiced Islam.

“I am a Muslim, and there is nothing Islamic about killing innocent people in Paris, San Bernardino or anywhere else in the world,” Ali said. “True Muslims know the ruthless violence of so-called Islamic Jihadists goes against the very tenets of our religion.

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“We, as Muslims, have to stand up to those who use Islam to advance their own personal agenda. They have alienated many from learning about Islam. True Muslims know or should know that it goes against our religion to try and force Islam on anybody.”

“I am a Muslim, and there is nothing Islamic about killing innocent people in Paris, San Bernardino or anywhere else in the world.”

One of the main principles of Trump’s campaign has been taking a hard line on immigration. In the wake of the San Bernardino, California, mass shooting that killed 14 people last week, Trump called for the establishment of a national Muslim database and for restrictions on Muslims wishing to travel to the United States.

Ali’s political views did not endear him to the establishment in the 1960s, and his affiliation with the Nation of Islam ignited controversy during his reign as world heavyweight champion.

“Speaking as someone who has never been accused of political correctness,” Ali said, “I believe that our political leaders should use their position to bring understanding about the religion of Islam and clarify that these misguided murderers have perverted people’s views on what Islam really is.”

This article originally appeared in Religion News Service.