Umno leaders have defended their president, Prime Minister Najib Abdul Razak against the scathing criticism by former PM Dr Mahathir Mohamad.

Pulai MP Nur Jazlan Mohamed says there is little proof that Najib's losing support while Sabah speaker Salleh Said Keruak said using 1Malaysia Development Bhd and the purchase of the new government jet to attack Najib is unfair.