Sudan's truce in jeopardy as airstrikes continue.

A three-day ceasefire in Sudan has been threatened by airstrikes and renewed fighting, with a senior aid worker warning of a "huge biological hazard" resulting from the armed seizure of a Khartoum laboratory containing deadly diseases. The violence has pitted army units loyal to its military ruler against the Rapid Support Forces. The UN has warned that the fighting could "engulf the whole region and beyond". The violence has left many residents stranded in their homes with dwindling food and water supplies, and has forced the UN humanitarian office to cut back on some of its activities.