At least 30 “drug dealers” have been killed since Rodrigo Duterte was sworn in as the president of Philippines Thursday, according to the police, sparking outrage amongst human rights activists.

The police also announced the seizure of nearly $20 million worth of narcotics.

Duterte, known as "the punisher," won the election in May on a platform of crushing crime. However, his advocacy of extrajudicial killings has alarmed many. After his oath taking, Duterte said he wanted to get rid of drug traffickers, telling supporters to “go ahead and kill them yourself as getting their parents to do it would be too painful.” In the past, he has also offered rewards to those who “shoot” them.

Al Jazeera reported Duterte’s top police commander, Ronald dela Rosa, telling officers accused of drug links that he would not hesitate to change their birthdays to Nov. 2—the Day of the Dead, a major religious holiday in Catholic Philippines.

Oscar Albayalde, police chief for the Manila region, said five drug dealers were killed Sunday in a gun battle with police in a shanty town near a mosque near the presidential palace. “My men were about to serve arrest warrants when shots rang out from one of the houses in the area,” Albayalde told reporters, saying police returned fire and killed five men.

Four guns and 200 grams of crystal methamphetamine were recovered.

In the north of the main island of Luzon, drug enforcement agents and police seized a shipment of 180 kilograms (400 pounds) of “shabu” (methamphetamine) worth about $19.2 million from either China or Taiwan, Rosa said.

Three other people were killed in other areas in Manila on Sunday and 22 were killed in four areas outside the capital. More than 100 people have died in the stepped up anti-crime drive since the election on May 9. Most of these have been suspected drug dealers, rapists and car thieves.

Azadeh Shahshahani, a human rights lawyer who has monitored rights abuses in the Philippines, told Al Jazeera that the killings set a “worrisome trend.”

“The president and his subordinates should remember that the accused should be afforded a fair process in an independent court of law regardless of the severity of the offence, per well-established principles of international law,” Shahshahani, a director of the US-based group Project South, said.

Edre Olalia, secretary general of the National Union of People’s Lawyers, said the killings must be halted.

“The drug menace must stop … Yet the apparent serial summary executions of alleged street drug users or petty drug lords which appear sudden, too contrived and predictable must also stop,” he said in a statement. “The two are not incompatible.”