An Umno group opposed to party president Najib Abdul Razak, has threatened to burn the party's constitution if no action is taken against Kedah Umno members who rebelled against Menteri Besar Mukhriz Mahathir.

"We will hold a huge protest and burn the Umno constitution (because Umno) toyed with it. You take action against some, but don't take action against others," Gabungan Ketua Cawangan Malaysia (GKCM) deputy president Mohd Zin Mustapa said.