Saudi Foreign Minister Adel al-Jubeir saying he is aware of Prime Minister Najib Abdul Razak's claims that monies deposited into Najib's private accounts are donations, does not mean that he agrees it is true, said former premier Dr Mahathir Mohamad.

"In case Najib’s supporters failed to note, the question is whether al-Jubeir is aware of the background and details about the donation.

"Accordingly, the Saudi foreign minister replied, 'We are aware of the donation and it is a genuine donation with nothing expected in return'," Mahathir wrote in his blog today.

Najib's arch-enemy also noted that al-Jubeir had said he was aware that attorney-general Mohamed Apandi Ali had found no wrongdoing in Najib receiving the donation.

"Being aware of the statements of the A-G does not mean he agreed with the statement," Mahathir said, adding that al-Jubeir also did not retract or negate his previous remarks doubting the RM2.6 billion donation's origins.

"It is the Malaysian media which interpreted his awareness as a negation of his previous statement," he said.

Al-Jubeir previously said that he did not think the RM2.6 billion was a political donation nor did it come from the Saudi government.

Instead, the minister said the money was from an unspecified "investment" in Malaysia.

Najib had repeatedly claimed the billions of ringgit in his personal accounts was a political donation from Saudi Arabia.

The prime minister and his supporters have accused detractors, namely Dr Mahathir Mohamad, of harping on the issue with aim of toppling Najib from power.