Thousands of Filipinos have rallied for and against President Rodrigo Duterte whose policies, including a heavy-handed war on drugs, have made him both controversial and hugely popular.
Riot police were deployed across the capital Manila on Thursday to keep rival protesters apart amid fears of possible confrontation between the two sides.
Anti-Duterte protesters used the 45th anniversary of the start of late Ferdinand Marcos's dictatorship to warn that the current president would one day deliver on his threat to declare nationwide military rule.
Left-wing and human rights groups rallied in numerous areas of the capital, including at the foot of a bridge leading to the presidential palace. A few thousands marched at a university area, yelling "Never again, never again to martial law."
Duterte supporters also turned up in large numbers to demonstrate, reflecting his popularity among many who see him as an ant-corruption hero.
"This is to tell the people that 'here we are, we are the majority who are happy with the government and not those few who are just griping'," rally organizer Benny Antiporda told Reuters.
Millions of Filipinos admire Duterte's down-to-earth style, his no-nonsense approach and even his imperfections. His supporters see him as a champion of ordinary people and the best hope for change.
He is popular in the country by those who are weary of widespread crime and corruption. In his election campaign last year, Duterte pledged to eradicate narcotics by killing up to 100,000 drug traffickers and addicts.
Rights groups say the anti-narcotics crackdown has triggered unwarranted violence, with thousands of other people being murdered in unexplained circumstances.
Duterte also placed the entire southern third of the country under martial law in May to deal with the siege of Daesh-linked militants in the city of Marawi that has dragged on for nearly four months now.
His opponents on Thursday criticized his pro-China stance and the destruction in Marawi by military airstrikes. Others decried what they see as his cozy relationship with the still-powerful Marcos family.
Duterte has warned he would use force or expand martial law if public order were threatened.
On Wednesday, he said he had ordered law enforcers to kill his own children, two of whom serve as mayor and vice mayor of his southern home city, if they were found to be involved in illegal drugs.
The tough-talking politician once threatened to “burn down” UN headquarters in New York after the body criticized the "extrajudicial killings" by government-sanctioned death squads in the Philippines.