Western countries including Britain, the United States, France and Germany on Friday urged both sides in war-torn Sudan to let in "urgently required" aid to millions of people in dire need.
War has raged since April 2023 between the Sudanese Armed Forces (SAF) under the country's de facto ruler Abdel Fattah al-Burhan and the paramilitary Rapid Support Forces (RSF), led by his former deputy Mohamed Hamdan Daglo.
Both sides have been accused of war crimes, including targeting civilians and blocking humanitarian assistance.
"The two sides' systematic obstruction of local and international humanitarian efforts is at the root of this famine," European and North American nations said in a joint statement.
The countries asked for movement restrictions on the Adre border crossing from Chad, where the United Nations says it has trucks waiting, to be lifted.
It also called for "all possible cross-border routes" to be opened "without impediment", which both warring sides previously committed to.
"We condemn that, despite the overwhelming urgency, both SAF and RSF persist in obstructing the humanitarian response," they said in the declaration, signed by the European Commissioner for Crisis Management.
"An immediate and coordinated scale-up of assistance, together with full, safe and unhindered humanitarian access to populations in need, is urgently required to mitigate the large-scale loss of life," they added.
The conflict has left tens of thousands dead and forced more than 11 million people to flee their homes, including nearly three million now in other countries, according to the United Nations.
Around 26 million people face severe food insecurity, with famine declared in the Zamzam displacement camp in Sudan's western Darfur region.
Several rounds of negotiations have so far failed to put an end to the conflict.