During a 9/11 commemoration ceremony at the Pentagon on Wednesday, President Donald Trump sent a brutal warning to terrorists, warning them to never return to the United States.

Breitbart reported that during Trump’s speech, he admitted that he had peace talks scheduled with the Taliban at Camp David, but added that he called them off as soon as the terrorist group claimed responsibility for a suicide bombing in Kabul that killed 12 people, including one American soldier.

“They thought they would use this attack to show strength, but actually what they showed is an unrelenting weakness,” Trump said.

Trump went on to say that in the days since the Kabul attack, America had escalated attacks against the Taliban as he would continue to fight terrorism. Trump made it clear that he has no intention of allowing terrorists to gain entry into the U.S. again.

“If for any reason, they come back to our country, we will go wherever they are, and use power, the likes of which the United States has never used before,” Trump said.

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Trump then clarified that he was not talking about nuclear arms, but vowed retaliation.

“They will never have seen anything like what will happen to them,” Trump warned. “No enemy on earth can match the overwhelming strength skill and might of the American armed forces.”

The president went on to give thanks to the heroes of the military who continue to fight terrorism overseas every single day.

“They have crossed seas, climbed mountains, trekked through deserts, and rushed into enemy compounds to face down the threat of radical Islamic terrorism,” Trump said, honoring the nearly 7,000 service members who have died in the fight against terrorism.

“We do not seek conflict, but if anyone dares to strike our land, we will respond with the full measure of American power and the iron will of the American spirit, and that spirit is unbreakable,” Trump said.

On the 18th anniversary of the September 11 terrorist attacks, Trump also took to Twitter to honor the victims and our country.

“Today and every day, we pledge to honor our history, to treasure our liberty, to uplift our communities, to live up to our values, to prove worthy of our heroes, and above all, to NEVER FORGET,” he tweeted.

Today and every day, we pledge to honor our history, to treasure our liberty, to uplift our communities, to live up to our values, to prove worthy of our heroes, and above all, to NEVER FORGET. #Honor911 pic.twitter.com/3xbEvl92py

— Donald J. Trump (@realDonaldTrump) September 11, 2019