The Hague, Netherlands — Former Philippine president Rodrigo Duterte failed to attend in person at the International Criminal Court on Friday at the opening of the crimes against humanity hearing over his deadly crackdown on narcotics.

The 79-year-old, the first ex-Asian head of state to face charges at the ICC, followed by videolink during a short hearing to inform him of the crimes he is alleged to have committed, as well as his rights as a defendant.

Sounding frail and wearing a blue suit and tie, he spoke briefly to confirm his name and date of birth. Presiding Judge Iulia Motoc allowed him to follow proceedings in absentia due to his long flight to The Hague.

His lawyer Salvador Medialdea told the court his client had been "abducted from his country."

"He was summarily transported to The Hague. To lawyers it's extrajudicial rendition. For less legal minds it's pure and simple kidnapping," said Medialdea. 

Medialdea also said Duterte was suffering "debilitating medical issues," adding: "Other than to identify himself, he is not able to contribute to this hearing."

Duterte appeared sleepy during the proceedings, closing his eyes frequently for long periods.

But Motoc told Duterte: "The court doctor was of the opinion that you were fully mentally aware and fit". She set a date of September 23 for the next stage of the process, a hearing to confirm the charges.

Duterte stands accused of the crime against humanity of murder over his years-long campaign against drug users and dealers that rights groups said killed thousands.

In the prosecutor's application for his arrest, he said Duterte's alleged crimes were "part of a widespread and systematic attack directed against the civilian population in the Philippines."

"Potentially tens of thousands of killings were perpetrated," the prosecutor alleged of the campaign that targeted mostly poor men, often without proof they were linked to drugs.

Victims' families have welcomed the trial as a chance for justice, while Duterte supporters believe he was "kidnapped" and sent to The Hague amid a spectacular fall-out with the ruling Marcos family.

A group of family members, lawyers and human rights activists was to gather in Manila to watch a livestream of the ICC hearing, said organisers Rise Up and the Duterte Accountability Campaign Network.

'Kill all of you'

According to international law experts, his whirlwind arrest and surrender to the ICC offers a welcome boon to the embattled court, which is being attacked from all sides and sanctioned by the United States.

"I see the arrest and handing over of Duterte as a gift at an important moment in time," Willem van Genugten, Professor of International Law at Tilburg University in The Netherlands, told AFP.

Earlier Friday, his daughter Sara Duterte, vice president of the Philippines, said she had submitted a last-minute bid to get the hearing moved.

"We are praying and hoping that the court will grant our request to move the initial appearance just so that we can properly sit down with the former president and discuss the legal strategies since we haven't talked to him yet," she told AFP outside the court.

Duterte supporters gathered outside the hulking glass building in the Hague shouting "bring him home."

But Ecel Sandalo, an anti-Duterte demonstrator, told AFP the fact the former president was on trial had given him "hope that despite all the injustices in the world, there are still small victories that we can celebrate."

As he landed in The Hague, the former leader appeared to accept responsibility for his actions, saying in a Facebook video: "I have been telling the police, the military, that it was my job and I am responsible."

In his application for arrest, the prosecutor quotes from some of Duterte's pronouncements when he was running for president.

He is cited as saying the number of criminal suspects killed "will become 100,000... I will kill all of you" and the fish in Manila Bay "will become fat because that's where I will throw you."

At the confirming of charges hearing, a suspect can challenge the prosecutor's evidence.

Only after that will the court decide whether to press ahead with a trial, a process that could take several months or even years.

(Source: Richard CARTER / Charlotte VAN OUWERKERK, AFP)