The number of refugees fleeing violence in South Sudan to Uganda has passed the one million mark, the UN says.
The organisation is appealing to the international community for "urgent additional support".
It adds that at least another one million refugees have fled to Sudan, Ethiopia, Kenya, Democratic Republic of the Congo and Central African Republic.
South Sudan has been wracked by civil war, which has seen numerous atrocities, since 2013.
In July of that year, President Salva Kiir fired his deputy Riek Machar, and in December accused him of planning a coup - an allegation he denied. Forces loyal to the two men then started fighting.
Uganda's welcoming attitude towards refugees has been praised by the UN and other international organisations. The government, for example, gives South Sudanese a plot of land to build a home and farm.
In 2016, Uganda received more refugees than any other country in the world.