Sudanese caught in the crossfire are struggling to find food, shelter, and medical care as the conflict in Sudan continues.

Aid agencies on Tuesday also raised increasing alarm about the crumbling humanitarian situation in a country reliant on outside help.

Al Jazeera’s Hiba Morgan, reporting from Khartoum, said that there are areas throughout the Sudanese capital where the ceasefire has not held. Heavy clashes have been reported in the vicinity of the presidential palace and the general command of the army.

“A hospital was hit in the city of Omdurman [north of Khartoum] following an artillery strike; at least a dozen people have been injured and the hospital was closed,” she said, adding that patients and the injured were evacuated to another hospital 3km (1.9 miles) away.

A series of short ceasefires during the past week have either failed outright or brought only intermittent lulls in the fighting that has raged between forces loyal to the country’s two top generals since April 15.

The recent lulls in fighting have been spread out enough for dramatic evacuations of hundreds of foreigners by air and land, which continued on Tuesday.

But they have brought little or no relief to millions of Sudanese caught in the crossfire, struggling to find food, shelter and medical care as explosions, gunfire and looters wreck their neighbourhoods.

In a country where a third of the population of 46 million already needed humanitarian assistance before the fighting, multiple aid agencies have had to suspend operations and dozens of hospitals have been forced to shut down.

The UN refugee agency said it was gearing up for potentially tens of thousands of people fleeing into neighbouring countries.

Meanwhile, the World Health Organization expressed concern on Tuesday that one of the warring parties had seized control of the central public health laboratory in Khartoum.

“That is extremely, extremely dangerous because we have polio isolates in the lab. We have measles isolates in the lab. We have cholera isolates in the lab,” Nima Saeed Abid, the WHO representative in Sudan, told a UN briefing in Geneva by video call from Port Sudan.

He did not identify which side held the facility but said they had expelled technicians and power was cut, so it was not possible to properly manage the biological materials. “There is a huge biological risk.”

Escaping the violence

Calls for negotiations to end the crisis in Africa’s third-largest nation have been ignored. For many Sudanese, the departure of diplomats, aid workers and other foreigners and the closure of embassies are signs that international powers expect the mayhem to only worsen.

Thousands of Sudanese have been fleeing Khartoum and its neighbouring city of Omdurman. Bus stations in the capital were packed Tuesday morning with people who had spent the night there in hopes of getting on a departing bus.

Drivers increased prices, sometimes tenfold, for routes to the border crossing with Egypt or the eastern Red Sea city of Port Sudan. Fuel prices have skyrocketed, to $67 a gallon ($17.70 a litre) from $4.20 ($1.11 a litre), and prices for food and water have doubled in many cases, the Norwegian Refugee Council said.

The new 72-hour ceasefire, announced by US Secretary of State Antony Blinken, was to last until late Thursday night, extending a nominal three-day truce over the weekend.

The US said it is confident it can exert influence in Sudan to push the warring parties there to reduce their fighting.

In an interview with Al Jazeera on Tuesday, White House national security spokesperson John Kirby said Washington will remain involved in finding a resolution to the crisis and continue to work with regional partners.

“We’re pretty confident that we can have an influence here,” Kirby said, noting that the US helped broker a 72-hour ceasefire on Monday.

“We’ve got a stake here; we’ve got an interest at the table; and we’re going to continue to use that and the United States’s convening power to try to get these two sides together to get the violence down.”