Philippines President Rodrigo Duterte, center, at a visit to a military camp in the southern Philippines on Sept. 20, 2016. (EPA)

The Philippine president, Rodrigo Duterte, has already lobbed insults in the direction of President Obama, Pope Francis and the European Union. Thursday's target: a Philippine senator investigating the violent deaths of some 3,000 people possibly linked to Duterte's calls for anti-crime purges.

The latest insult — a crass, sexually tinged quip about Sen. Leila de Lima — was cheered by some Duterte fans online. His backers have reveled in his jabs despite diplomatic fallout such as Obama calling off a planned meetings during a trans-Pacific summit earlier this month.

But a presidential spokesman on Thursday urged Duterte's supporters to stop harassing both de Lima and journalists. Be "responsible" with words, he said.

It seems the president missed the memo.

"She was not only screwing her driver, she was screwing the nation," the president said in a jab at allegations over her personal life,  according to a translation by the Inquirer, a Manila-based paper.

De Lima, a longtime Duterte critic, has investigated alleged death squads during his time as mayor of the southern city of Davao. This summer, she launched an investigation into the wave of extra-judicial killings linked to his call to "kill all" the country's criminals.

In a Senate hearing last week, de Lima presented a witness who claimed to have served as a contract killer for Duterte. She was quickly demoted. In a subsequent hearing, she was accused of taking bribes from drug dealers and her address and phone number were broadcast live on national television. She says she now fears for her life.

Phelim Kine, deputy Asia director for Human Rights Watch, called her ouster "a craven attempt to derail accountability for the appalling death toll from President Duterte's abusive ‘war on drugs.’”

In recent weeks, de Lima's critics — and much of the press — have zoomed in on rumors about her personal life, alleging she was having an affair with her driver. On Thursday, at the inauguration of a power plant, Duterte said that de Lima's critique of his rights record was a bid to build her career at his expense and was hurting the country.

Last month the president suggested she commit suicide. ''If I were de Lima, ladies and gentlemen, I'll hang myself,' he said.

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