Human Rights Watch (HRW)'s Deputy Director of Asia, Phelim Kine, shows a copy of the HRW magazine during a news conference in Kabul. REUTERS/Omar Sobhani/Files

MANILA – A human rights watchdog has decried President Rodrigo Duterte’s comments referencing Nazi party founder Adolf Hitler and the Holocaust, calling his words "obscene."

Human Rights Watch (HRW) Deputy Asia Director Phelim Kine also urged the United States and European Union (EU) to send a strong message to the Duterte administration that the Philippines "risks an immediate suspension of aid unless the abusive 'war on drugs' and its skyrocketing death toll comes to a halt."

The US and EU are among the Philippines' sources of official development assistance.

The public should not underestimate the impact Duterte's words have on police and vigilantes, Kine said.

Vigilantes "lawlessly slaughter their fellow Filipinos without fear of arrest," said Kine, and they are encouraged by Duterte’s strong words.

On Saturday, the US State Department said Duterte's comments regarding Hitler were "troubling."

His words were "a significant departure" from the tradition of America and the Philippines' "mutual foundation of shared values…[including] our shared belief in human rights and human dignity," said State Department Spokesperson Mark Toner.

The United Nations also weighed in, with spokesperson Stephane Dujaric saying, "Any use of the Holocaust and the suffering of the Holocaust in comparison to anything else frankly is inappropriate and is to be rejected."

In a statement, Presidential Spokesperson Ernesto Abella said Duterte's reference to the killing of over 6 million Jews during World War II "was an oblique deflection of the way he has been pictured as a mass murderer, a Hitler, a label he rejects."

"The Philippines recognizes the deep significance of the Jewish experience especially their tragic and painful history," he said. "We do not wish to diminish the profound loss of 6 million Jews in the Holocaust - that deep midnight of their story as a people."

On Friday, Duterte told reporters upon his arrival from an official visit to Vietnam that critics portrayed him as a "cousin of Hitler."