In addition, almost 170 people have been injured.
Earlier, a death toll of 19 people was stated.
Monusco, the UN peacekeeping force, has been criticized for what is seen as a failure to stop the fighting in the country’s conflict-torn east. The UN blames the unrest on criminal groups who claim to be protesters.
The UN headquarters in Goma in eastern Congo-Kinshasa was stormed at the beginning of last week and the protests have continued since then.