An anti-government group on Thursday unveiled its three essential demands ahead of next week's planned rally at the Democracy Monument, saying it was open to negotiations with the government.
The group said it wanted the resignation of Prime Minister Prayut Chan-o-cha, the passage of amendment bills to pave the way for a brand new charter and reforms of the monarchy.
Activist Arnon Nampa said Wednesday's rally, which coincides with the anniversary of the Oct 14, 1973 popular uprising, would be protracted but that the group was ready to negotiate.
Now that the group had spelt out its demands, the ball was in the government's court and Prime Minister Prayut Chan-o-cha should decide what to do next, Mr Arnon said.
He urged the public to converge at Democracy Monument at 2pm on Oct 14 and "seize back" the monument from the Bangkok Metropolitan Administration (BMA), which has landscaped the politically symbolic landmark with decorative plants and flowers to keep people from occupying the area.
He said he expected the gathering to be larger than the crowd who turned out for the Sept 19-20 rally at nearby Sanam Luang because he thought many people from the provinces would travel to the capital to take part.
The protest organisers were reported to have initially estimated that the turnout could even exceed a million people.
Mr Arnon insisted the protest would be peaceful and orderly.
"I'm asking groups [planning to commemorate the Oct 14, 1973 uprising] who have a common stance to join the rally," he said.
"I promise there will be surprises and we'll fight until we win. We've come so far and we won't give up."
Mr Arnon said he did not envisage the protesters marching from the Democracy Monument to other venues but their plans could change depending on how the situation develops and the number of protesters.
Asked how protesters would react if MPs accepted a coalition amendment bill sponsored by coalition parties but did not alter the first or second chapters of the constitution, he said they wouldn't mind as long as it sought to create a new charter.
Meanwhile, Adul Khiewboriboon, chairman of a support group for relatives of the Black May 1992 victims, on Thursday submitted a petition to the Democrat Party asking it to withdraw from the coalition government and thus force MPs to vote on choosing a new prime minister.
He said he was optimistic of a positive response from the Democrat Party, which currently has 53 MPs from both the single-constituency and party-list systems.
It was time for the Democrats to walk away from the government, which would necessitate a new administration and a new premier, Mr Adul said.
Mr Adul added, however, that it found their call for reforms of the monarchy to be "misplaced".
Responding to Mr Adul's call, Democrat spokesman Ramet Rattanachaweng said the party was sensitive to public opinion and noted that its objective of joining the coalition was to work for the public interest.