The feasts and festivities of the Muslim holy month of Ramadan have been muted in Sudan this year with millions of people displaced from their homes and struggling with hunger as a war between the army and paramilitaries nears the one-year mark.

"All what we were accustomed to, how we eat, drink, meet people in Ramadan, ... all of that is no longer available," said Mohamed Ali, who broke his fast in a displacement centre in Port Sudan on the Red Sea, to which many have fled from the capital Khartoum and other active war zones.

In the past, Ramadan in Sudan was marked by large communal night-time gatherings. Now Ali and millions of others rely on community kitchens from volunteers for a pared-down Iftar meal.

The war in Sudan, which is approaching its first anniversary, broke out last Ramadan between the country's army and the Rapid Support Forces, the result of long-simmering tensions during four years of power-sharing.

Now more than 8.5 million people have been displaced by the fighting, according to the UN, and about 18 million face worsening acute hunger.

The war has tested the Sudanese reputation for generosity and hospitality.

"This war has... scared some people away, but it did not stop others from staying as they are, opening their doors and houses for anyone to come inside," said Sheikh Khalid Abdul Rahman, an imam in Omdurman, a city that has seen intense fighting in recent weeks.

The United States has said it hopes to resume peace talks after Ramadan, though previous rounds have not succeeded in achieving a lasting ceasefire.

"Everyone has had enough of war. We need, God willing with his power, to stop the war once and for all," said Hanan Hassan at a community kitchen in Omdurman.