A follow up on the arrest of former Philippine President Rodrigo Duterte.

Supporters rallied outside the air base where the firebrand former leader was being held on Tuesday after he was arrested at the request of the International Criminal Court.

Authorities scaled up security with dozens of police guarding the Villamor Air Base where Duterte's supporters had gathered and chanted slogans.

Duterte was served an interpol arrest warrant on his arrival at Manila's main airport and was in custody, the Office of President Ferdinand Marcos Jr. said in a statement on Tuesday.

Duterte questioned why he was being arrested.

“So what is the law and what is the crime I committed? Show to me now the legal basis for my being here as I apparently was brought here not of my own volition. It's somebody else's...So you have to answer now for the deprivation of liberty,” said Duterte.

The arrest follows years of Duterte taunting the ICC since he unilaterally withdrew the Philippines from the court's founding treaty in 2019 as it started looking into allegations of systematic extrajudicial killings on his watch.