Family and supporters of former Philippine president Rodrigo Duterte will rally Friday to mark his 80th birthday and protest against his detention in The Hague on a charge of crimes against humanity.
Duterte could spend the remainder of his life in jail if convicted at the International Criminal Court (ICC) of the charge tied to his "war on drugs" in which thousands were killed.
Supporters are planning more than 200 simultaneous birthday rallies demanding his release.
Presidential palace spokeswoman Claire Castro however warned pro-Duterte protesters that they were "bordering the line of inciting to sedition".
Castro said that Philippine officials wished Duterte "good health, good fortune", but added that "he needs that."
Philippine Vice President Sara Duterte, his eldest daughter, has been in the Dutch city since shortly after his arrest helping assemble his legal team.
In a birthday message, Sara Duterte said her father "knows he will face the ICC with the Filipino people", adding that the support "makes the challenges he is facing today more bearable".
Another of the ex-president's daughters, 20-year-old Veronica, as well as her mother, Cielito Avancena, said they failed to get inside the prison to see him this week -- but remained hopeful.
Veronica Duterte said her father had "always been a force to be reckoned with, even in his sunset days", in a post on social media.
"We will make certain that his legacy lives on", she added.
- 'Systematic attack' -
The ICC chief prosecutor's application for his arrest 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.
But Sara Duterte has said that the once wildly popular president is convinced that what the ICC did "was wrong and there is no case to begin with".
Duterte's arrest on March 11 and rapid handover to the international tribunal came on the heels of his family's bitter falling out with his successor, President Ferdinand Marcos.
Cracks began to appear in their alliance soon after Marcos teamed up with Sara Duterte to sweep the presidential and vice presidential elections in May 2022.
The vice president quit her cabinet post as education secretary after being denied the defence portfolio, while Duterte himself began calling Marcos a drug addict.
Last month, Sara Duterte was impeached by a pro-Marcos House of Representatives on charges that include an alleged assassination plot against the president.
The outcome of her Senate trial will likely depend on the number of seats her allies win in May 12 mid-term elections.
One of her party's candidates, former Philippine police chief and drug war enforcer Ronald Dela Rosa, says he expects to be arrested by the ICC next.
The ex-president faces a six months wait inside the United Nations' Scheveningen prison before his next scheduled court appearance on September 23.
The court session will confirm the charges against him and allow him to contest the allegations.
Chief ICC prosecutor Karim Khan has disclosed 181 unspecified items of evidence to the defence, led by British-Israeli lawyer Nicholas Kaufman.
The prisoner is only allowed two visits per day -- a lawyer and a family member, the vice president said.
"I urged him to write a book and then when you get out, we'll sell it and make money out of it," she said.
