South Ossetian opposition leader Alla Dzhioyeva accused the incumbent authorities of breaking the deal with the opposition a day after it was reached.
The situation in restive South Ossetia, which declared independence from Georgia in 2008, heated up after Dzhioyeva won the November 27 runoff against a Kremlin-backed rival, according to preliminary results. Two days later, the republic's Supreme Court annulled the voting results, citing violations.
Supporters of Dzhioyeva, who has declared herself president despite the court's ruling, have been holding demonstrations on the main square of the republic's capital, Tskhinvali, ever since.
South Ossetian President Eduard Kokoity, who has led the breakaway republic since 2001, announced his resignation on Saturday under a deal reached with the opposition. A number of high-ranking state officials were sacked.
Dzhioyeva said late on Saturday she disagreed with some of appointments Kokoity made before stepping down, including the "instant" nomination of new Constitutional Court members.
"We retain the right to waive the previously reached agreements, as they are not being observed by the authorities," Dzhioyeva said.
Her supporters, who were to leave the central Teatralnaya Square of the capital Tskhinvali under the deal, continue their protest.
"People say they are going to stay, and I'm not going to argue with them," the ex-presidential candidate said.
Dzhioyeva said she and her supporters would demand for a meeting with the republic's acting head, Vadim Brovtsev right after he assumes the post on Sunday, and demand him to cancel Kokoity's nominations.
