Dr Mahathir a leader with 'super ego' - PM Najib

"If he fights, he must win, tries to win. Now he is not successful, he will be more aggressive with his words," he said in a special interview held in conjunction with the 2016 UMNO General Assembly.

The one-hour session was moderated by Hamdan Ahmir and participated by Utusan Malaysia Editor Datuk Zulkefli Hamzah and RTM television personality Sayed Munawar Sayed Mohd Mustar.

Najib who is also UMNO President said Dr Mahathir's efforts to topple him through the Mahathir Declaration failed because it was legally and constitutionally invalid and rejected by the Meeting of the Council of Rulers last month.

As such, Najib said, Dr Mahathir had no choice but to attack him as he felt that to destroy UMNO, the party president must first be toppled.

"When Dr Mahathir was the UMNO President, the same people who are with him today said he was really worse. If we look back at the tapes, their old videos, they said Dr Mahathir was worse.

"This is the process of politics, political games. So now that he has not succeeded, he will be more aggressive in his words," said Najib.

Asked to share his secret of facing the condemnations calmly, Najib said: "I understand leaders like Dr Mahathir, his methods and message (that he uses)."

Najib also said the strong support from the party members as well as Barisan Nasional Parlimentary Members were also factors which helped him.