Suthep, a key leader of the ongoing protest against the controversial amnesty bill, said he and his fellow protest leaders are ready to fight against the government and it was thus not necessary for them to hide behind the protection that MP status affords.
Before resigning, they paid homage to a statue in front of the Democrat Party headquarters.
He said the group had informed Democrat leader Abhisit Vejjajiva and Democrat chief adviser Chuan Leekpai for acknowledgement but not for approval.
"We will not move protesters from Rajdamnoen rally site yet. We will call for people to gather there, and then make a decision based on the situation," he said.