“Aidan is in good shape, thanks be to God,” Mr Martin told reporters at a press conference in Belfast.

“We do have a number of Irish citizens in Sudan, many working with international organisations, Aidan is a UN ambassador in Sudan. We're keeping obviously a very close eye on their wellbeing,” he said.

Mr O’Hara joined the Department of Foreign Affairs in 1986 and took up the role of Ambassador to Ethiopia, South Sudan, and the African Union in 2012.

The incident comes as the Sudanese capital has been engulfed by explosions and gunfire over the last three days, as the army and a powerful rival force battled in the streets for control of the country.

“The situation is very, very fraught in Sudan,” said Mr Martin, adding that the safety of Irish citizens in the country was “paramount” and he appealed for “both sides to cease all hostilities”.

“I would ask the protagonists to heed the words of the UN secretary-general in respect of ending the violence and engaging in talks.

“Obviously, it's very difficult to leave the country right now (with) the situation at the airport in Khartoum.

“We’re hoping to keep the situation, with our colleagues within the European Union and with the United Kingdom, we'll continue to monitor that and obviously from our perspective, the safety of our citizens is paramount.”

At least 185 people have been killed and over 1,800 wounded since the fighting erupted, UN envoy Volker Perthes said.

The toll could be much higher because there are many bodies in the streets around central Khartoum that no one can reach because of the clashes.

There has been no official word on how many civilians or combatants have been killed.

The sudden explosion of violence over the weekend between the nation’s two top generals, each backed by tens of thousands of fighters, trapped millions of people in their homes or wherever they could find shelter, with supplies running low in many areas.

The two sides are using tanks, artillery, and other heavy weapons in densely populated areas.

Fighter jets swooped overhead and anti-aircraft fire lit up the skies as darkness fell.

Top diplomats on four continents scrambled to broker a truce, with the UN Security Council set to discuss the crisis.

Mr Martin has said his Department, including its Embassy in Nairobi, “will continue to monitor the situation closely, and to work with our partners in the region, within the European Union, and at the United Nations, to seek to end the violence.”

It comes as earlier today Sudan’s rival commanders agreed a 24-hour ceasefire, from this evening, after pressure from US Secretary of State Antony Blinken over the deadly fighting that saw shots fired at a US diplomatic convoy.

The ceasefire will start at 6pm (4pm GMT) and will not extend beyond the agreed 24 hours, Army General Shams El Din Kabbashi, a member of Sudan's ruling military council, said on al Arabiya TV.

Mr Blinken held separate calls with the rival commanders - the army chief and the head of the paramilitary Rapid Support Forces (RSF) - whose power struggle derailed an internationally-backed plan to shift to civilian rule after decades of autocracy and military control.

Blinken, speaking in Japan, said he had telephoned both RSF leader General Mohamed Hamdan Dagalo, known as Hemedti, and General Abdel Fattah al-Burhan, appealing for the 24-hour ceasefire "to allow the Sudanese to be safely reunited with families" and to provide them with relief.

The Secretary of State said a US convoy was attacked despite the vehicles being marked with diplomatic license plates and bearing American flags. Initial reports suggest the attack was undertaken by forces associated with the RSF, he said, calling the action "reckless". Blinken said all US personnel were safe after the incident.

After the call, Hemedti said the RSF approved the ceasefire to ensure the safe passage of civilians and the evacuation of the wounded.

In a post on Twitter, Hemedti said he had "discussed pressing issues" with Blinken and more talks were planned. The RSF also issued a statement saying it was waging a battle to restore "the rights of our people" in what it called a new revolution.

Hemedti's whereabouts have not been disclosed since fighting began.

A previous shorter ceasefire agreed for Sunday was not fully observed. Artillery volleys, strikes by combat aircraft and street fighting have made it almost impossible to travel in Khartoum, trapping residents and foreigners in their homes.

The main international airport has been under attack, halting commercial flights.

Fighters have attacked aid workers, hospitals and diplomats, including EU Ambassador Aidan O’Hara. Three workers for the World Food Programme were killed in the fighting on Saturday, and a UN plane was hit in crossfire.

The International Federation of Red Cross and Red Crescent Societies said it was nearly impossible to provide humanitarian services around the capital. It warned that Sudan's health system was at risk of breakdown.

Additional reporting by Reuters.