Manila. Former Philippine President Rodrigo Duterte was arrested at Manila's international airport Tuesday on order of the International Criminal Court in connection with a case of crime against humanity filed against him, the Philippine government said.

Duterte was arrested after arriving from Hong Kong and police took him into custody on orders of the ICC, which has been investigating the mass killings that happened under the former president's deadly crackdown against illegal drugs, President Ferdinand Marcos' office said in a statement.

“Upon his arrival, the prosecutor general served the ICC notification for an arrest warrant to the former president for the crime of crime against humanity,” the government said. “He’s now in the custody of authorities."

The surprise arrest sparked a commotion at the airport, where lawyers and aides of Duterte loudly protested that they, along with a doctor and lawyers, were prevented from coming close to him after he was taken into police custody. “This is a violation of his constitutional right,” Sen. Bong Go, a close Duterte ally, told reporters.

The warrant of arrest sent by the ICC to Philippine officials, a copy of which was seen by The AP, said “there are reasonable grounds to believe that" the attack on victims "was both widespread and systematic: the attack took place over a period of several years and thousands people appear to have been killed.”

Duterte’s arrest was necessary “to ensure his appearance before the court,” according to the March 7 warrant, adding that the former president was expected to ignore a court summons.

It said that although Duterte was no longer president, he “appears to continue to wield considerable power.”

“Mindful of the resultant risk of interference with the investigations and the security of witnesses and victims, the chamber is satisfied that the arrest of Mr. Duterte is necessary.”

Duterte's arrest and downfall stunned and drove the families of the victims of his bloody crackdowns against illegal drugs to tears.

“This is a big, long-awaited day for justice,” Randy delos Santos, the uncle of a teenager killed by police during an anti-drug operation in August 2017 in the Manila metropolis, told The Associated Press.

“Now we feel that justice is rolling. We hope that top police officials and the hundreds of police officers who were involved in the illegal killings should also be placed in custody and punished,” delos Santos said.

Three of the police officers who killed his nephew, Kian delos Santos, were convicted in 2018 for the high-profile murder, which prompted Duterte at the time to temporarily suspend his brutal anti-drugs crackdown.

The conviction was one of at least three, so far, against law enforcers involved in the anti-drugs campaign, reflecting the concerns of families of victims of suspected extrajudicial killings that they would not get justice in the Philippines, hence, their decision to seek the help of the ICC.

It was not immediately clear where Duterte was taken by the police and when he would be flown to Europe to be handed to ICC custody. The government said the 79-year-old former leader was in good health.

The ICC began investigating drug killings under Duterte from Nov. 1, 2011, when he was still mayor of the southern city of Davao, to March 16, 2019, as possible crimes against humanity. Duterte withdrew the Philippines in 2019 from the Rome Statute in a move human rights activists say was aimed at escaping accountability.

The Duterte administration moved to suspend the global court’s investigation in late 2021 by arguing that Philippine authorities were already looking into the same allegations, arguing the ICC — a court of last resort — didn’t have jurisdiction.

Appeals judges at the ICC ruled in 2023 that the investigation could resume and rejected the Duterte administration’s objections. Based in The Hague, the Netherlands, the ICC can step in when countries are unwilling or unable to prosecute suspects in the most heinous international crimes, including genocide, war crimes, and crimes against humanity.

President Ferdinand Marcos Jr., who succeeded Duterte in 2022 and became entangled in a bitter political dispute with the former president, has decided not to rejoin the global court. But the Marcos administration has said it would cooperate if the ICC asks international police to take Duterte into custody through a so-called Red Notice, a request for law enforcement agencies worldwide to locate and temporarily arrest a crime suspect.