Mr Suthep announced at the government complex, the main rally site, that he would not prolong the protest any longer but would make it clear on Monday that demonstrators will "win or lose".
"It will be the final battle. It will be do or die for us. If we fail [to overthrow the government], I will give up and turn myself in to police," he told demonstrators.
Mr Suthep called on Thai people in every corner of the country to take to the streets on Monday to "regain the people's sovereignty" from what he said was an illegitimate government and parliament.
"D-Day time will be 9.39am. You, Bangkokians, just leave your homes in the morning and march along the roads, all roads in Bangkok, to the same destination - Government House, and we will not return here [to the government complex].
"For people in the provinces, their destinations will be the provincial halls. We will surround Government House and all provincial halls. We will not let this government do its work any more as it is no longer legitimate," Mr Suthep declared.
He also told those who do not want to join the protest march to stay home on Monday, as he predicted the traffic in Bangkok on Monday morning would be bad as he expected all roads to be full of people marching.
He said he and the protesters had fought long enough, "I cannot stand to see you [protesters] suffer any longer. Monday, December 9 will be the do-or-die day for all of us. If millions of people come out and join us, then we will win; otherwise, we will lose and that will be the end for me. I will walk into jail on the insurrection charge."
He said he will lead the march to Government House himself.
The government, he added, has adopted tough measures and violence against protesters so he did not want any of them to be injured or lose their lives, especially as there are many elderly people at the demonstration.
"I want to tell you the truth," Mr Suthep told the crowd. "No matter how much stamina we have, we may be wounded or die if we don't have enough people."
Meanwhile, the Lawyers' Association yesterday petitioned the Constitution Court to order the People's Democratic Reform Committee led by Mr Suthep to end its rallies and to consider dissolving the opposition Democrat Party.
Association president Narinpong Jinapak said he had submitted a petition asking the court to consider whether Mr Suthep, Democrat leader Abhisit Vejjajiva and the Democrat Party as a whole had used unconstitutional means to try and seize power.
Mr Abhisit yesterday accused Ms Yingluck of duplicity, saying her actions ran counter to her calls for talks with anti-government protesters.
It followed clashes which left a protest guard and two anti-government protesters badly injured on Thursday night and yesterday morning.
The Bangkok Emergency Medical Service (BMES) yesterday confirmed that two men, aged 18 and 35, were injured on Thursday night and yesterday morning during clashes between youths and protest guards at Kok Wua intersection.
The 35-year-old man, identified as Sornchai Tuksuwan, suffered severe injuries to his hands in an explosion, while the 18-year-old, whose name was withheld, sustained multiple stab wounds to his torso.
Mr Sornchai was sent to Klang Hospital, while the teenager was recovering at Vajira Hospital, the BMES said.
Klang Hospital director Chuwit Praditbatuka yesterday said Mr Sornchai was in stable condition, although some of his fingers may have to be amputated.
In a separate clash at the Finance Ministry, Bangchong Pengsakul, a 46-year-old guard of the anti-government demonstration, was shot in the left arm.
He was sent to Rajavithi Hospital.
All three of the injured have undergone surgery and are now in stable condition.