“I know the truth, just own up,” said Najib to a crowd of about 5,000 at a health ministry event in rural Penang Island.

He said he had been amused by a video showing the reaction of Parti Amanah Negara president Mohamad Sabu (a former ISA detainee) and PKR president Dr Wan Azizah Wan Ismail, when Mahathir had denied ordering the ISA arrests.

The ISA, repealed by Najib’s government, had provided for detention without trial for renewable two-year periods.

On several occasions Dr Mahathir has denied he was responsible, while Home Minister and Prime Minister, for the police sweep and detention of more than 100 people in Operation Lallang in 1987.

Najib said today: “I said, you must admit that it was you that ordered the arrests. You must take the responsibility. You cannot go around saying the police made the arrests.

“If the home minister does not give permission the police would not arrest (the political foes under the ISA). I know this because I am the prime minister.

“If you still say you did not, I know the truth. Just own up,” he said.

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