Suspended Umno deputy president Muhyiddin Yassin and vice-president Shafie Apdal may be in hot water with the Malay party after the duo signed the Citizens' Declaration calling for party president Najib Abdul Razak to step down.

The Star Online reported that Umno may call an emergency meeting to discuss the fate of Muhyiddin and Shafie, quoting supreme council member Hassan Malek who said that Najib may call for an emergency meeting to address the issue.

"We usually have a meeting once every month, but I believe this calls for an emergency meeting. We need to do something about this because if you want to be with us, you work with us and support us. It's very bad otherwise," he was quoted as saying.

Hassan said the action of the duo had embarrassed the party and it must be handled as the party would brook no enemy within its fold.

"We were humiliated by the actions of the suspended party deputy president and the vice-president. They forgot that these were the main enemies and now they are sitting together with them to sign this declaration.

"We can't tolerate all this nonsense and we certainly do not want to have an enemy within the party," he was reported to have said.

Yesterday, former prime minister Dr Mahathir Mohamad and Muhyiddin joined several dozen opposition leaders, BN rebels, and civil society figures in signing the declaration urging Najib to be removed from power by all legal means possible.