Although President Donald Trump is “not at all” worried about a possible confrontation with Iran, he cautioned Iran would suffer if it did something “foolish.”

"We have the greatest people in the world, we have the greatest equipment in the world. We have the greatest ships — the most deadly ships, we don’t want to have to use them, but they’re the most deadly ships ever conceived,” Trump told reporters Friday when asked if he was anxious about conflict with Iran, according to the White House press pool report. “And we hope for their sake they don’t do anything foolish. If they do, they will pay a price like nobody’s ever paid a price.”

The comments come after the Trump administration claimed that the Navy’s amphibious assault ship Boxer took defensive action against a drone in the Strait of Hormuz on Thursday, after the drone got within 1,000 yards of the ship and ignored requests to back off.

“A fixed-wing unmanned aerial system approached Boxer and closed within a threatening range,” chief Pentagon spokesman Jonathan Hoffman said in a written statement. “The ship took defensive action against the UAS to ensure the safety of the ship and its crew.”

Trump said Thursday that the episode was one of self-defense because the drone was “threatening the safety of the ship and the ship’s crew.”

But the U.S. and Iran are at odds over the incident, and Iran claimed that none of its drones were lost.

“We have not lost any drone in the Strait of Hormuz nor anywhere else,” Deputy Foreign Minister Abbas Araghchi tweeted early on July 19. “I am worried that USS Boxer has shot down their own UAS by mistake!”

Despite Iran’s certainty, Trump doubled down Friday and reiterated the U.S. took out the drone. National Security Adviser John Bolton also added there is “no question” that the drone belonged to Iran.

Tensions between the U.S. and Iran have escalated in recent months, particularly after Iran shot down a U.S. surveillance drone on June 20. Trump said he was preparing to launch a military strike against Iran in retaliation, but claimed he canceled the mission once he learned how many casualties were expected.

Iran has accused the U.S. of waging an “economic war” against it, after the Trump administration pulled out of the 2015 Iran nuclear deal. The pact put limits on Iran’s nuclear program, but lifted sanctions imposed against Iran.

However, stringent sanctions were reimposed after the U.S. withdrew from the deal in May 2018.