The Philippine president, Rodrigo Duterte, has said he would have his son killed if drug trafficking allegations against the younger politician were true, and that the police who carry out the hit would be protected from prosecution.

Paolo Duterte, 42, appeared this month before a senate inquiry to deny accusations made by an opposition lawmaker that he was a member of a Chinese triad gang who helped smuggle in a huge shipment of crystal methamphetamine from Chinainfo-icon.

Duterte did not refer to the allegations specifically but reiterated his statement from last year's election campaign that none of his children were involved in drugs, but they would face the harshest punishment if they were.

"I said before my order was: 'If I have children who are into drugs, kill them so people will not have anything to say,'" Duterte said in a speech on Wednesday night in front of government workers at the presidential palace in Manila.

"So I told Pulong [Paolo's nickname]: 'My order is to kill you if you are caught. And I will protect the police who kill you, if it is true,'" he said.Duterte, 72, won the presidential electionsinfo-icon on a brutal law-and-order platform in which he promised an unprecedented campaign to eradicate illegal drugs in society by killing up to 100,000 traffickers and addicts.

Since he assumed office in the middle of last year, police have reported killing more than 3,800 people in anti-drug operations while thousands of others have been murdered in unexplained circumstances.

Thousands of his critics and supporters held rival rallies on Thursday, taking national debates over his deadly drug warinfo-icon and martial-law threats to the streets.Police in battle uniforms were mustered to keep order as protesters held a series of rallies across Manila, using the 45th anniversary of late dictator Ferdinand Marcos imposing martial law to say

Duterte was equally violent and authoritarian.

"Our country is turning into a graveyard. People are getting killed every day and we bury the dead every day, just like in the time of Marcos," anti-Duterte protest leader Pedro Gonzales said.But supporters of Duterte also turned up in large numbers, reflecting his popularity with many Filipinos who see him as a charismatic, anti-establishment politician who is their best chance to quell crime and corruptioninfo-icon.

As president, Duterte has said he would be "happy to slaughter" 3 million drug addicts, and described children shot dead in the drug war as "collateral damage". But he has also repeatedly insisted he has never instructed police to do anything illegal, and that they must only kill in self-defence.

The anti-Duterte protesters were backed by the political opposition and leaders of the Catholic church, the country's dominant religioninfo-icon, signalling a rising opposition to Duterte.Leni Robredo, the vice-president, and Benigno Aquino, Duterte's predecessor - both critics of the incumbent leader - attended a separate mass on Thursday for those killed in the drug war. "The good part of this is there are so many people concerned, from different ages," Aquino told reporters.

Archbishop Socrates Villegas, president of the Catholic Bishops' Conference of the Philippinesinfo-icon, denounced the drug killings at another mass on Thursday, saying Catholics must do more than lighting candles for the dead and helping orphans. "Stand up. To keep quiet in the face of evil is a sin," he said.