Human rights groups have condemned the Philippine president for saying troops should shoot female communist rebels in the genitals to render them “useless”.

Left-wing group Karapatan said Rodrigo Duterte “has distinguished himself as a frothing-in-the-mouth fascist who incites the worst violations of international humanitarian law”.

Mr Duterte’s remarks “are but the latest of the series of this madman’s display of tyranny, lunacy and machismo”, Karapatan secretary general Cristina Palabay said.

US-based group Human Rights Watch said the remark was the latest in a “series of misogynist, derogatory and demeaning statements he has made about women” that encourage state forces to commit sexual violence during armed conflicts.

In a rambling speech before surrendered communist rebels, Mr Duterte spoke about the futility of their decades-old insurgency and how his administration could help them return to normal life.

He also asked why women join the insurgency and abandon their families.

At one point, he said without elaborating: “Tell the soldiers. There’s a new order coming from the mayor. We won’t kill you. We will just shoot your vagina so that … if there is no vagina, it would be useless.”

The remarks elicited laughter from the audience.

Mr Duterte spoke in the Bisaya dialect. An official transcript of the president’s speech issued by the government omitted the word “vagina” and expletives from his remarks.

A long-time mayor of Davao city, where he built a reputation for his tough approach to criminality and his brash, often sex-laden remarks, Mr Duterte has acknowledged his rough ways but suggested many Filipinos have come to accept him.

Western governments and human rights watchdogs have expressed alarm over his crackdown on illegal drugs, which has left thousands of mostly poor suspects dead.

He has lashed out at critics, including European governments, which he told “to go to hell” for imposing conditions on financial aid.

He said he has told European officials he will not attend an upcoming meeting between south-east Asian and European leaders.

“They say that I have a bad mouth. It’s true. They say that I’m not a statesman, not fit for a president, and that’s true,” Mr Duterte said in a speech, referring to his critics.

“But the problem here is that I won.”

Steve Rood, a Manila-based political analyst, said many Filipinos like Mr Duterte’s unorthodox style and his charm when he talks to them in an intimate way, as if his speeches were not being broadcast.

With crime easing and recent public surveys showing satisfaction with his administration, the president’s opponents may do better if they focus on issues such as traffic jams in the capital and rising rice prices, he said.

“A focus on President Duterte’s colourful language is not the productive way to engage the Philippine domestic audience,” Mr Rood said.