Hundreds of protesters marched in Manila on Friday and marked International Human Rights Day by destroying an effigy of Philippine President Rodrigo Duterte.
The demonstration came a day after Philippine Supreme Court largely upheld on Thursday the legality of an anti-terrorism law that opponents fear could threaten democracy and muzzle dissent, but struck down a provision preventing street protests, activism and labour strikes from being branded as terrorism by authorities.
Protesters held placards with slogans like "Stop the killings", "Defend press freedom" and "Junk terror law".
Before it was destroyed, the effigy depicted Duterte with horns alongside presidential candidate Ferdinand "Bong-bong" Marcos Jr and vice-presidential candidate Inday "Sara" Duterte.
Protest leader Renato Reyes said the "the state of human rights in the Philippines is very bleak", and questioned why Duterte had been invited to U.S. President Joe Biden's Summit for Democracy this week.
Thursday's court decision, only portions of which were released, was generally welcomed by government officials.
Many Filipinos remain hypersensitive to any threat to democracy more than three decades after an army-backed "people power" revolt ousted dictator Ferdinand Marcos Sr in massive pro-democracy protests that became a harbinger of change in authoritarian regimes across the world.
Known as the Anti-Terrorism Act of 2020, the law allows the detention of suspects for up to 24 days without charge and empowers a government anti-terrorism council to designate suspects or groups as suspected terrorists who could then be subject to arrest and surveillance.
It replaces a 2007 anti-terror law called the Human Security Act which was rarely used, largely because law enforcers feared a provision that imposed a fine of 500,000 pesos ($10,000) for each day they wrongfully detained a terrorism suspect.
Opponents filed 37 petitions asking the court to declare the current law, which was signed by Duterte in July last year, unconstitutional.
But except for at least two provisions, the court declared in a statement that all the other parts of the law which came under legal challenge "are not unconstitutional."
Twelve of the 15 justices voted to strike out a line that says public protests, dissent, work stoppages and other exercises of political rights would not be considered as acts of terrorism as long as these "are not intended to cause death or serious physical harm ... or to create a serious risk to public safety."
They said the qualifying conditions were "overbroad and violative of freedom of expression."
Nine justices also declared it was unconstitutional for the anti-terrorism council to be allowed to designate people and groups as terrorists based on the requests of other countries or international organisations.