U.S. officials on Friday blasted Philippines president Rodrigo Duterte for comparing himself approvingly to Nazi leader Adolf Hitler, according to CNN.

{mosads}Secretary of Defense Ash Carter called Duterte’s comments “deeply troubling,” though he added that the bilateral relations between the two countries “served the interests of our nations for many years now.”

He also said that he had a productive discussion about  “ongoing alliance operations” with Philippines.

Duterte on Friday sparked outrage by comparing his war on drugs with the Holocaust and stating that he wants to “slaughter” millions of drug addicts.

“Hitler massacred three million Jews. Now there is three million, what is it, three million drug addicts [in the Philippines], there are,” Duterte said during a speech in Davao City.

“I’d be happy to slaughter them. At least if Germany had Hitler, the Philippines would have [me]. You know my victims, I would like [them] to be all criminals, to finish the problem of my country and save the next generation from perdition.”

State Department spokesman Mark Toner also said that U.S. finds the remarks “very troubling.”

“While there [are] these remarks occasionally being made, at the working level our relationship remains very strong and very vital,” he added.