Along with the 36 deaths, government spokesman Patrick Muyaya is reported by AFP as saying that "nearly 170" people had been wounded in anti-UN protests.
The latest toll marks an increase on an earlier reported figure of 19 people killed during the protests.
Last week, deadly demonstrations demanding the departure of the UN peacekeeping mission, known as MONUSCO, took place in several towns in eastern DRC.
Anger has been fueled by perceptions that MONUSCO is failing to do enough to stop decades of armed conflict. More than 120 militias operate in the DRC's troubled east.
On Sunday, three people were also killed after UN peacekeepers opened fire during an incident in eastern Congo and the Uganda border.
An earlier death toll of two has since risen to three, according to the government statement.
The peacekeepers, coming back from leave in Uganda, opened fire before opening the barrier and crossing the border at Kasindi, in Beni territory.
UN chief Antonio Guterres said he was "outraged" by the deadly incident and demanded "accountability".
In his statement, dated Monday, Muyaya said that Congolese President Felix Tshisekedi had expressed to Guterres his "total disapproval" of the peacekeepers' behavior at the border post and urged that the culprits be "severely punished".