The Japanese government has sent a team to the Philippines to conduct a five-day study on ways to cooperate with the sometimes violent anti-narcotics campaign of President Rodrigo Duterte.

The 15-member mission is made up of officials from the Foreign Ministry, the National Police Agency, the health ministry, the Japan International Cooperation Agency and the Japanese Embassy in Manila.

Katsuyuki Kawai, a special adviser to Prime Minister Shinzo Abe, said during a welcome ceremony at the embassy Monday that the prime minister and Duterte agreed in October during their Tokyo summit that cooperating on anti-drug measures is important.

“We are confident that Japan is able to provide the highest, skillful assistance to the Philippines in its fight against drugs,” Kawai said, adding that the mission includes noted experts and researchers from Japan.

According to the embassy, the mission will hold discussions with Philippine government agencies in Manila and in Davao, Duterte’s hometown, where he was mayor for more than 20 years.

After the ceremony, Kawai and the delegation visited a government-run drug treatment and rehabilitation facility, the largest of its kind, in Taguig in the suburbs of Manila.

The facility takes care of more than 1,200 patients, most of whom are suffering from addiction to methamphetamine hydrochloride.

Kawai said Japan has been treating drug addicts with “cognitive behavior therapy, especially psychotherapy” for the last 10 years.

“That treatment has been implemented at domestic prisons almost 100 percent nationwide,” he said. “Japan has achieved the world’s biggest success in drug abuse prevention and educational activities.”

Bien Leabres, head of medical services at the facility, said his staff are happy to have help from Japan.

Leabres said Japan can help address their need for infrastructure, particularly in creating additional dormitories since the facility is currently accommodating more than double its capacity, and other necessities such as supplies and vehicles. Japan can also help in the training and development of the staff, he said.

Leabres said that Japan is the second country, following Britain, to express willingness to aid the center.

Kawai met Duterte later Monday. They had previously met when Duterte visited Japan, at which time a planned visit to a rehabilitation center for drug addicts did not materialize.

Duterte’s flagship program has been an intense campaign against illegal drugs, criminality and corruption.

Philippine lawmakers have criticized the way Duterte is carrying out the campaign, saying it should be done within the bounds of the law and he must punish erring police officers.

The police say 2,004 people have been killed by officers in self-defense during anti-drug operations since Duterte took office July 1. Another 3,060 killings have been classified as “under investigation.”

Senators said while they had found no clear proof that the rising number of extrajudicial killings was state-sponsored, they told Duterte to observe due process and give the accused their day in court. Duterte has denied the police are conducting extrajudicial killings.

But at the same time, he has welcomed the death toll. In September, he said he’d be “happy to slaughter” 3 million drug addicts.

He has repeatedly told the police to “kill” accused drug dealers if they resist violently, or if officers feel their lives are in danger.

“The war against illegal drugs must be won within the legal system, and the president must lead in reminding the people of this important message,” the senators said in a report after conducting an inquiry into extrajudicial killings.