The German government told the Philippine ambassador that comments by President Rodrigo Duterte likening his deadly crime war to Hitler's efforts to exterminate Jews were "unacceptable."
Duterte, 71, won elections in May in a landslide after a campaign dominated by his pledge to eradicate drugs in society by killing tens of thousands of people.
In comments Friday, he drew parallels between his campaign to wipe out the drug problem and Adolf Hitler's genocidal drive.
"Hitler massacred three million Jews. Now there are three million drug addicts (in the Philippines). I'd be happy to slaughter them," Duterte told reporters in his home city of Davao.
"At least if Germany had Hitler, the Philippines would have," he said, then paused. "But you know, my victims, I would like to be (sic) all criminals to finish the problem of my country and save the next generation from perdition."
Nazi Germany slaughtered some six million Jews by the end of World War II.
The German foreign ministry said in a statement that it had asked the Philippine envoy "to come to the ministry for a discussion on this issue."
"Any comparison of the singular atrocities of the Holocaust with anything else is totally unacceptable," ministry spokesman Martin Schaefer told reporters earlier and reiterated in the statement.
Germany, Europe's top economy, has expressed serious concerns about Duterte's crackdown, which has left more than 3,000 people dead in three months and threatened a breakdown of the rule of law in one of Asia's most chaotic democracies.