A nurse was killed and a health worker severely injured while responding to an Ebola alert in Congo, the World Health Organization said. The Associated Press and BBC News reported the attack. It happened Saturday in the town of Bafwasende in eastern Tshopo province.

BBC News said local youths accused the workers of contaminating water sources and spreading Ebola, according to UN-backed Radio Okapi. WHO Director General Tedros Adhanom Ghebreyesus condemned the violence. Authorities say attacks on responders are hampering efforts to slow the fastest-growing Ebola outbreak in the world.

Uganda has tightened its border as the Congo outbreak spreads, BBC News noted. Health teams need community trust to find cases early. Violence against nurses undercuts that work and delays treatment.

What we know: Attackers killed a nurse and badly hurt another worker during an Ebola response in Congo.
What we don't: Whether suspects have been arrested, and how the outbreak toll will shift this week.