The deadly clashes took place mostly on Monday in the capital Kinshasa, and other cities when members of the separatist sect Bundu dia Kongo (BDK) staged a rally against President Joseph Kabila.
Security forces fired shots into crowds to disperse the protesters in Kinshasa, killing 11 BDK members and 10 bystanders, according to HRW in a statement on Thursday.
Others were killed in similar clashes in the southwestern cities of Matadi and Muanda, HRW added.
The rights group called for “prompt and impartial investigations” to determine who is responsible for the deaths.\
“Violence by protesters or excessive use of force by security forces should not be tolerated and those responsible should be held accountable,” HRW Central Africa director Ida Sawyer said.
BDK is just one of the many opposition groups threatening peace and stability in the vast, mineral-rich central African country after it plunged into chaos when the president failed to organize fresh presidential elections and refused to step down when his mandate expired in December.
President Kabila’s ruling coalition and opposition leaders then agreed that the presidential election would take place by the end of this year. However, delays in registering voters and mobilizing financing make that increasingly unlikely.
The country is still reeling from conflicts between 1996 and 2003 in which millions of people were killed.