He was referring to the "partial victory" he claimed had been achieved by anti-government street rallies that begun 34 days ago.
"This is a victory but it's not a decisive victory," he added.
Several thousands of his supporters jammed the complex on Chaeng Wattana Road and more at Democracy Monument after they easily occupied Government House and the Metropolitan Police Bureau hours earlier.
He praised them for their relentless efforts to fight tear gas, and water cannon and rubber bullet shots in trying to lay siege to the two key targets of the demonstrations - one symbolising the power of police siding with the "Thaksin regime" and another signifying the centre of the administration.
"We seized them with our hands," he said.
But Mr Suthep reminded the crowds that the rallies must go on until the Shinawatra family is no longer involved in Thai politics.
The self-proclaimed secretary-general of the People's Democratic Reform Committee made clear that the resignation of Prime Minister Yingluck Shinawatra, or the dissolution of parliament, would not be enough to end the protests, which he said would go on until the "Thaksin influence" is swept from the country.
"Our determination is to wipe out the 'Thaksin regime' from the country," he said.
The veteran politician predicted that Ms Yingluck would step down or declare a snap poll by dissolving the House of Representatives and attempting to garner support by blaming protesters for continuing their street campaign and for stopping the country from returning to normal.
"A dissolution of parliament does not mean anything for us," he went on.
Ms Yingluck's resignation would simply clear the way for another Thaksin associate to run the country and a new election would see the same group of MPs return to parliament through vote-buying, he said.
"We have come this far and that will not be a waste," he said. "The tyrants must be completely rid."
The protest leader called for patience from the crowd in achieving their final goal. "It will take time for us because we have only hearts and speakers. We will put this effort in once and for all, so that when we go home, we will go without doubts," he said.
The rallies will resume after Dec 5, he added.
Demonstrators and police greeted each other during Tuesday's peaceful anti-government protests, in sharp contrast to the violence and teargas on Monday. (Bangkok Post photos)