Jatuporn Prompan, chairman of the United Front for Democracy Against Dictatorship (UDD), said the situation had turned into anarchy on Friday.
What PDRC secretary general Suthep Thaugsuban did on Friday was setting the stage for a coup.
He urged the red shirts to remain in position on Friday and attend the rally on Utthayan road on Saturday as planned.
Mr Jatuporn also said earlier he would invite Yingluck Shinwatra to join the rally but it has not been confirmed whether the former prime minitser would join.
Nattawut Saikuar, UDD's secretary general, said the situation was not beyond his expectation.
The PDRC would continue to provoke and resort to using force and violence to achieve its end, he said.
Therefore, it is important the red shirts avoid confrontation.
Tida Tawornseth, a UDD adviser, said the red shirts rejected all unelected leaders and anarchy was what Mr Suthep was after.
Kwanchai Praipana, chairman of the red-shirt Rak Udorn Group of Udon Thani province, said his group would bring 1,000 people to join the Utthayan rally on Saturday.
The red shirts rallied and burned mock coffins and effigies in several provinces on Friday in protest against the moves by the Constitutional Court and the National Anti-Corruption Commission to disqualify Yingluck Shinawatra as prime minister.
The rallies took place in Samut Prakan, Pathum Thani, Ang Thong, Ayutthaya, Nakhon Sawan, Lop Buri, Nakhon Ratchasima, Sukhothai, Chiang Mai, Lampang, Khon Kaen, Phitsanulok, Kamphaeng Phet, Nan, Maha Sarakham, Amnat Charoen, Si Sa Ket, Buri Ram, Ubon Ratchathani, Uthai Thani, Sing Buri and Roi Et provinces.
Between 100 and 200 demonstrators showed up at each protest location.
They criticised the Constitutional Court for dismissing Ms Yingluck and nine ministers of the cabinet on Wednesday.
Some protesters also blasted the NACC for deciding on the following day to impeach Ms Yingluck for her poor performance in administering the reportedly graft-plagued money-losing rice-pledging scheme.
Red-shirt demonstrators accused the court and the NACC of destroying democracy and a government elected by the people.
They cursed the court and the commission and burnt effigies and mock coffins with photographs of Constitutional Court judges and NACC members before ending their gatherings.
The UDD plans a big rally on Utthayan Road in Nakhon Pathom on Saturday. The nearby Buddha Monthon Buddhist park is a main venue for activities to mark Visakha Puja Day commemorating the birth, enlightenment and death of Buddha, from Friday until May 13.