WARRI, Nigeria (AP) — Women in southern Nigeria have marched in the streets to protest the deaths of several women in hotel rooms by what appears to be a serial killer.

The women, many dressed in black, held the second day of protests Wednesday in the city of Port Harcourt in the oil-producing Niger Delta region.

Rivers State police spokesman Nnamdi Omoni says eight women have been strangled in different hotel rooms in the state in the past two months. He says some suspects have been arrested but a manhunt continues to identify the main culprit.

Activists assert, however, that up to 20 women have been killed and say the protests will continue until security is restored.