Prime Minister Najib Abdul Razak should be detained under the Security Offences (Special Measures) Act (Sosma) for undermining democracy, former premier Dr Mahathir Mohamad said.

"Khairuddin Abu Hassan was questioned and detained (under Sosma for lodging police reports on 1MDB).

"I think that Najib should also be questioned by police and detained under Sosma and for a longer time (than Khairuddin).

"He is the one who is destroying and undermining the democratic process [...] democracy is being destroyed because of Najib, not us," Mahathir said during a talk at Kampung Baru in Kuala Lumpur tonight.

He claimed Najib was undermining democracy by preventing people from speaking about issues such as 1MDB, particularly during the Umno annual general assembly which opens tomorrow.

Mahathir said he would attend the Umno AGM though to hear the tabling of the party's accounts.

"I want to see if the RM2.6 billion donation (Najib received) is in the accounts. If it's not, where is it?" he said.

Mahathir was speaking at the gathering which was held in support of Umno deputy president Muhyiddin Yassin.

For this year, Umno decided to do away with the tradition of having the party number two officiate the party wings' respective AGMs, thus taking away Muhyiddin's opportunity to address them tomorrow.

The party has yet to decide if he can deliver a winding-up speech on the last day of the assembly on Saturday.

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