More than 1,000 people in the Philippine capital Manila have marked the anniversary of a 1986 revolt by protesting against the government of President Rodrigo Duterte.
Left-wing activists and opposition supporters rallied at the spot where crowds forced dictator Ferdinand Marcos to flee after a 20-year rule.
The protesters condemned Mr Duterte's brutal anti-drugs crackdown.
The president's supporters held a rival rally at Manila's Rizal Park.
Among those who joined crowds at the scene of the 1986 People Power Revolution were Mr Duterte's predecessor Benigno Aquino and current vice-president Leni Robredo.
Ms Robredo resigned from Mr Duterte's cabinet in December after she was barred from cabinet meetings due to differences with the president.
Mr Aquino and Ms Robredo are both supporters of Duterte critic Senator Leila de Lima, who was arrested on Friday on drugs charges. She strongly denies any wrongdoing.
In a message from her detention cell, Ms de Lima said: "There is a president who is threatening to re-impose martial law and openly support the killings of thousand of people.
"The grim truth - in the last seven months under Duterte, there were more deaths compared to the 14 years of martial law under the Marcos regime."
Left-wing politician Emmi De Jesus said opponents of President Duterte would stand their ground "against efforts to revert to dictatorship".
"The pile of bodies in the Duterte government's war on drugs; arrests and killings of political activists; renewed push for death penalty, and militarisation of communities affecting women and children is nothing but a U-turn to full-blown fascism," she said.
Anti-government demonstrators also massed near the national police headquarters in Manila.
President Duterte angered many Filipinos last year when he allowed Ferdinand Marcos to be interred in the Heroes' Cemetery in Manila.
The president called Marcos - who was accused of abducting and killing thousands of opponents - a "Filipino soldier".
Mr Duterte launched his nationwide war on the drugs trade in July last year and critics say he has encouraged police, vigilantes and mercenaries to shoot suspected drug dealers and users on sight. More than 7,000 people are believed to have been killed.
However, the president continues to enjoy a high level of backing among Filipinos.
His supporters held a vigil in Rizal Park late on Saturday to show approval for his crackdown on drugs.