Philippines President Rodrigo Duterte, famous for throwing insults at major world figures,  has called the UN Human Rights chief a “son of a whore” with a big, empty head.

His remarks came in a row over international criticism of the Philippine leader’s deadly drug war.

Pointing to his own head Duterte said: “Look, you have a big head but it’s empty. There is no gray matter between your ears. It’s hollow. It’s empty. It cannot even sustain a nutrient for your hair to grow because his hair here is gone”

RT reports: The remark, made during a Tuesday speech, was in reference to UN Human Rights Commissioner Zeid Ra’ad Al Hussein.

Last month, Zeid hit out at the tough-talking leader, saying he needed a “psychiatric evaluation,” while also slamming the Philippines leader for verbally attacking UN rapporteur Agnes Callamard with “the foulest of language.”

“Hey son of a whore, you commissioner, I need to go to a psychiatrist?” Duterte said during the speech. “The psychiatrist told me: ‘You are okay, mayor. You are just fond of cursing,’” he said, referring to his former title. Duterte mentioned that he had been advised to refrain from commenting on Zeid’s remark, but said that he wanted to “seek revenge.”

The remarks come as the UN leads a probe into alleged abuses and extrajudicial killings related to Duterte’s controversial war on drugs. It is being led by Callamard, who the Philippines leader said he would “slap” if she investigated him. Duterte has also ordered authorities not to cooperate with the probe.

Philippines police say they have killed around 4,100 suspects in anti-drug operations since July 2016. However, rights groups claim the number is three times higher and have accused the authorities of murder. In 2016, Duterte himself said he would be “happy to slaughter” drug addicts the same way Adolf Hitler slaughtered Jews. 

The “empty head” remarks are the latest in Duterte’s vast portfolio of insults aimed at world leaders. His greatest hits including calling former US President Barack Obama a “son of a b**ch/whore” and telling him to “go to hell.” He also threatened to “burn down the United Nations” and called former UN Secretary-General Ban Ki-moon a “devil.”

Its not just world leaders but also institutions that have come under fire from the Philippines President. Last year he spoke out about the Catholic Church, calling it corrupt, “full of sh*t” and accusing priests of sexual abuse.