There will be no disciplinary action taken on former Prime Minister Tun Dr Mahathir Mohamad, said UMNO secretary-general, Datuk Seri Tengku Adnan Tengku Mansor.

Tengku Adnan said there will be no action imposed on Dr Mahathir as long as no reports made by any UMNO members on him.

"We will only take disciplinary action if there is a report," he said when asked about the action against Dr Mahathir for making open criticism of party president, Datuk Seri Najib Tun Razak.

Tengku Adnan also hoped Dr Mahathir would avoid from openly criticising UMNO leaders unless he adopts to use proper channels to do so.

"Why do it (criticism) openly, it can be done personally," he said.

Yesterday, UMNO held a special press conference to express their support towards Najib, who is currently under fire since Dr Mahathir has brought the issue out in the open.

Dr Mahathir in a series of open criticisms has urged Najib to explain to the rakyat who had demanded for explanation on investment funds made by 1Malaysia Development Berhad (1MDB).

In addition, Dr Mahathir also urged for an investigation to be conducted on a statement made by a former member of the Special Action Unit (UTK) Corporal Sirul Azhar Umar who claimed he received orders to murder of Mongolian Altantuya Shaariibuu.

Last Friday, Najib in an interview once again reiterated that he never knew Altantuya.

While in 1MDB issue, Najib said he had ordered a forensic investigation conducted by the Auditor General and the Public Accounts Committee (PAC) of the points raised.