Hello and welcome to NewsHour.
It's coming to you live from the BBC World Service Studios in central London.
I'm Tim Franks.
We're going to begin the programme in the south-west of Sudan,
because it's there in the city of Nyala,
the capital of South Darfur state,
that it seems more than 70 healthcare workers are being forcibly detained,
along with at least 5,000 civilians.
That's prompted public concern from the head of the UN's World Health Organization,
Tedros Adanam Gebreyesus, and a call for their unconditional release.
I mentioned that Niala is the capital of South Darfur State.
It's also the unofficial capital of the paramilitary rapid support forces.
They've held the city for more than two years,
and it's their headquarters in the rolling battles against the Sudanese armed forces in the civil war which has spread such misery across this vast country.
indeed turned the place through brutality and siege,
killing and displacement into the world's biggest humanitarian crisis.
Earlier today, we managed to receive a voice note from one resident of Niala.
At his request,
we're withholding his identity and a translation of his words is voiced by one of the news our team.
Last Thursday,