Senator Leila De Lima on Friday said her arrest over drug allegations was President Rodrigo Duterte's way of silencing critics of his intensified campaign against illegal drugs that has killed at least 7,000 Filipinos nationwide.

"Clearly, this administration has evil and dangerous plans: to make an example of me to intimidate, silence, and destroy anyone who dares challenge them; to draw public attention away from the government’s abuses and failures; and to cover up their most murderous war on drugs," De Lima said in a video message recorded at the Senate prior to her arrest.

De Lima said Duterte has had a "fixation for revenge" against her after she called for an investigation against the alleged Davao Death Squad during her tenure as Commission on Human Rights chair.

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Duterte, in previous speeches, has been vocal about publicly taking down a certain human rights stalwart who has been after him since he was mayor of Davao City.

"The Filipino people know your style, Mr. President. To put the rule of law in your hands, silence your critics, and destroy those who will go against your caprices," De Lima said.

De Lima warned against the president's capacity to "destroy" the credibility and honor of those who stand against the administration's policies.

"If they can do this to a sitting Senator, what is stopping this administration from doing the same to ordinary Filipinos?" De Lima said.

The lady senator appealed to Filipinos to pray for the Philippines, and to safeguard the "fragile democracy against attempts to curtail our rights and freedom, and against the return of dictatorship.

"From all these violence, killings and crooked governance of the Duterte regime, clearly, I am not the Public Enemy No. 1 here, but this regime who has no respect for basic human rights, especially the right to life," she said.