Congo officials are vowing to round up those they say are responsible for violence and looting during street clashes over a delayed presidential election that left more than 40 people dead this week.

Police spokesman Col. Pierrot Mwanamputu said Wednesday the official death toll was 32, including four police officers. A Human Rights Watch researcher has said at least 44 people were killed.

Prosecutor Flory Kabange Numbi told reporters Wednesday that police have been instructed to search "everywhere" for suspects, even in hospitals.

Police say more than 100 people already have been arrested.

Thousands took to the streets of Congo's capital, Kinshasa, on Monday to oppose an election delay which some call a plot by President Joseph Kabila to stay in power after his mandate expires in December.