Originally Published: 18 APR 23 01:42 ET

Updated: 18 APR 23 10:28 ET

By Jessie Yeung, Teele Rebane, Rob Picheta, and CNN journalists in Sudan

(CNN) -- Gunfire, explosions and overhead fighter jets were heard across Sudan's capital Khartoum and nearby cities on Tuesday, amid conflicting reports of an agreed ceasefire.

Fighting between the country's armed forces and the paramilitary Rapid Support Forces (RSF) is in its fourth day in Khartoum near the army command and the presidential palace, and near two RSF bases to the north and west of the capital.

Residents remain trapped in the middle; 11 people were killed in North Darfur and dozens injured, including children, over the past 48 hours, medical charity Médecins Sans Frontières said.

For more than three days, students at the University of Khartoum have been trapped inside campus buildings as artillery and gunfire rain down around them in Sudan's capital. "It is scary that our country will turn into a battlefield overnight," said 23-year-old Al-Muzaffar Farouk, one of 89 students, faculty members and staff sheltering inside the university library.

Food and water are running low, but leaving is not an option -- one student has already been killed by gunfire outside. Khalid Abdulmun'em had been trying to run to the library from a nearby building when he was struck, said Farouk.

The students retrieved his body and brought it inside "despite the bullets that were falling on us," he added.

The university confirmed Abdulmun'em's death in a Facebook post, saying he had been shot in the campus' surroundings. In a separate post on Monday, the university urged humanitarian organizations to help evacuate dozens of people stranded on campus.

Khartoum has been wracked by violence and chaos in a bloody tussle for power between Abdel Fattah al-Burhan, Sudan's military leader, and Mohamed Hamdan Dagalo, also known as Hemedti, who is head of the RSF.

The two leaders have traded blame for instigating the fighting and breaking temporary ceasefires. Meanwhile, civilians are paying the price, with at least 180 people killed and 1,800 others injured, according to UN officials on Monday.

"I can see outside smoke rising from buildings. And I can hear from my residence blasts, heavy gunfire from outside. The streets are totally empty," said Red Cross staffer Germain Mwehu from Khartoum.

"In the building where I stay, I saw families with children, children crying when there are airstrikes, children horrified," Mwehu said, adding that people had little to no access to food or medicine given the fierce fighting outside.

Children are among those killed; a 6-year-old child died on Monday after the RSF shelled a hospital in Khartoum and damaged a maternity ward. Medics were forced to evacuate, leaving patients behind -- some just newborns in incubators.

At least half a dozen hospitals have been struck by both warring sides, according to Sudan's Doctors Trade Union.

Even diplomats and humanitarian workers have been targeted.

US Secretary of State Antony Blinken confirmed there was an attack on a US diplomatic convoy on Monday.

"Yesterday, we had an American diplomatic convoy that was fired on. All of our people are safe, but this the action was reckless, it was irresponsible and, of course, unsafe," Blinken said in a press conference on Tuesday.

The European Union ambassador to Sudan was also assaulted in his residency on Monday, though he is now doing fine, according to a spokesperson for the EU's top diplomat.

And three workers from the UN's World Food Programme (WFP) were killed in the western region of Darfur, prompting the WFP to temporarily halt all services in the country.

In statements early Tuesday morning, the two rival factions pointed fingers at each other.

The RSF accused the army of conducting airstrikes on residential neighborhoods and of attacking the EU ambassador's headquarters in Khartoum; meanwhile, the army accused the RSF of targeting the ambassador's residency, and of targeting the WFP's headquarters in Darfur.

Trying to broker peace

The UN and various foreign leaders have called for peace, with Blinken speaking separately with Burhan and Dagalo on Tuesday.

Blinken "expressed his grave concern about the death and injury of so many Sudanese civilians," and argued a ceasefire was necessary to deliver aid, reunify separated families, and ensure the safety of diplomatic and humanitarian staff, according to a readout from the US State Department.

The Sudanese Armed Forces later issued conflicting statements on a proposed 24-hour ceasefire, intended to go into effect later on Tuesday.

A statement citing the spokesperson on the official SAF Facebook page said the armed forces are "not aware of any coordination with mediators and the international community about a truce" and that the RSF announcement for a 24-hour truce "aims to cover up the crushing defeat it will receive within hours."

But Burhan told CNN earlier that the SAF will "adhere" to a ceasefire proposal by the tripartite mechanism, comprising of the United Nations Integrated Transition Assistance Mission in Sudan (UNITAMS), the African Union (AU), and the Intergovernmental Authority on Development (IGAD).

Dagalo meanwhile said on Twitter that a 24-hour ceasefire "to ensure the safe passage of civilians and the evacuation of the wounded" was approved by the paramilitary force.

The foreign ministers of G7 nations, comprised of some of the world's largest economies, urged the factions to "end hostilities immediately" in their joint statement from Japan on Tuesday.

Volker Perthes, the UN Secretary General's Special Representative for Sudan, said on Monday the organization has been trying to convince the two rival parties to "hold the fire" for a period of time, and asked them to protect embassies, UN offices, humanitarian and medical facilities.

Both sides had previously agreed to a three-hour ceasefire on Sunday, and again on Monday, with fighting resuming afterward, Perthes said.

But both Burhan and Dagalo have since accused the other of breaking that ceasefire.

When CNN spoke to Burhan on Monday afternoon, the sound of gunshots rang out in the background despite the supposed ceasefire -- and Burhan claimed Dagalo had violated it for the second day.

A spokesperson for the RSF rebutted the accusation, claiming that they had been trying to abide by the ceasefire, but "they keep firing which leaves no choice" but for the RSF to "defend itself by firing back."