A high-level international conference is due to get under way in London to find "a pathway to peace" in Sudan, hosted by the UK's Foreign Secretary David Lammy.
Sudan's civil war began exactly two years ago causing what aid agencies call the world's worst humanitarian crisis.
The UK is promising an extra $120m (£91m) worth of food and medical assistance.
Charities say 30 million people, many who are facing hunger, desperately need humanitarian aid.
More than 12 million have been forced from their homes and tens of thousands killed, amid reports of rape and ethnic cleansing.
In recent days, the Rapid Support Forces (RSF) launched an intense ground and aerial assault on camps for displaced people close to the city of el-Fasher in an attempt to seize the last state capital in Darfur held by their rival, the Sudanese army.
Zamzam, which has provided temporary shelter for an estimated 500,000 people, is now being systematically destroyed by fire from intentional arson by RSF forces, according to the Yale School of Public Health's Humanitarian Research Lab, which has analysed satellite images taken of the camp.
The RSF has not commented on the allegation.
Tuesday's ministerial conference is co-chaired by the UK, EU and African Union.
Officials say the aim is to unite international partners around a common position, to get more food and medicine into Sudan and find what Lammy calls a "pathway to peace".
Neither of Sudan's main warring parties - the Sudanese Armed Forces nor RSF - has been invited.
They will be represented instead by regional allies, some of whom diplomats say are fuelling the conflict. Among them is the United Arab Emirates (UAE), which is accused of arming the RSF, something it denies.
The war - a power struggle between the army and the RSF - began on 15 April 2023, after the leaders of the army and RSF fell out over the political future of the country.

Latest Stories
-
Robust anti-laundering fight critical for regional stability – Veep
4 hours -
Car ploughs into crowd outside LA nightclub, injuring 30
5 hours -
GNAT President calls for parliamentary legislation to protect reinstated PTAs
7 hours -
NPP Abanga blames his NDC twin brother for his misfortune
8 hours -
NPP Abanga breaks ranks to shield NDC twin brother in ‘galamsey’ accusations
8 hours -
Saminu Abdul Rasheed smashes national record again with 9.84s sprint in Georgia
9 hours -
Blekusu Coastal project: We’re reclaiming our coastlines – Housing Minister
12 hours -
Pricey plantains push Ghana’s market sellers to diversify
12 hours -
Full list: NPP delegates approve 54 reform motions, reject proposals on youth age, election supervision
12 hours -
WAFCON 2024: Cynthia made it easy – Chantelle hails goalkeeper after penalty saves
12 hours -
Cyber Security Authority boss suspended over use of military bodyguard
13 hours -
WAFCON 2024: I want to make history – Grace Asantewaa dreams of lifting the trophy
13 hours -
Afenyo-Markin accuses NDC of rebranding and claiming credit for NPP projects
13 hours -
2024 WAFCON: Grace Asantewa shines as Black Queens reach semis
13 hours -
WAFCON 2024: Ghana beat Algeria 4-2 on penalties to book semi-final spot for the first time since 2016
13 hours