Gunfire and fighting broke out in the Sudanese capital Khartoum, between the nation's army and a paramilitary group, Rapid Support Forces, following days of tension centering around a proposed transition to civilian rule.
Rapid Support Forces said it had taken control of Khartoum International Airport, the presidential palace and the residence of army chief General Abdel Fattah al-Burhan.
The army has said that RSF fighters are trying to seize the military headquarters.
"Clashes with the Rapid Support Forces are ongoing and the army is carrying out its duty to safeguard the country," army spokesman Brig. Gen. Nabil Abdallah told the AFP.
According to Al Jazeera, the Sudanese military special forces later said they have retaken control of the Khartoum airport from the RSF. The army said it has also taken control of one of the military bases earlier taken by the RSF.
Gunfire and explosions can be heard in videos taken by Khartoum residents and photos show rising smoke in Khartoum.
According to the Associated Press, tensions between the Sudanese army and RSF stem from a disagreement over how the RSF, headed by Gen. Mohammed Hamdan Dagalo, should be integrated into the military and what authority should oversee the process. The merger is a key condition of Sudan's unsigned transition agreement.
In a joint statement released Thursday, special envoys and representatives from France, Germany, Norway, the UK, U.S. and EU said they are concerned that heightened tensions and escalatory actions threaten to derail negotiations toward establishing a civilian-led government.
"We call on Sudan's military and civilian leaders to take active steps to reduce tensions. We urge them to hold to their commitments and engage constructively to resolve outstanding issues on security sector reform to establish a future unified, professional military accountable to a civilian government," the statement said.
"Establishing a civilian-led transitional government is essential to address Sudan's urgent political, economic, security and humanitarian challenges and is the key to unlocking international assistance," it added.
According to the Associated Press, clashes between the Sudanese military and RSF in recent months have forced the delay of signing the internationally backed deal to transition Sudan to civilian leadership.
Major parties in Khartoum have agreed on how to proceed with a transition of civilian government. U.S. Secretary of State Antony Blinken told reporters during a press conference in Hanoi, Vietnam that he spoke with General Burhan this week, saying he believes there is a real opportunity to move forward with the agreed upon framework, which the U.S. strongly supports. But, there are still some important remaining issues that need to be dealt with.
Blinken called it a fragile situation and said that there are other actors that may be pushing against progress, but said this is a real opportunity to finally carry forward the civilian led transition which the U.S. and other countries are trying to bolster.
"Deeply concerned about reports of escalating violence between the Sudanese Armed Forces and Rapid Support Forces. We are in touch with the Embassy team in Khartoum - all are currently accounted for. We urge all actors to stop the violence immediately and avoid further escalations or troop mobilizations and continue talks to resolve outstanding issues," Blinken said in a tweet on Saturday.
The U.S. Embassy in Khartoum is not currently evacuating U.S. nationals and advised those in Khartoum and surrounding areas to shelter in place and monitor the embassy's website and local media for security updates. Government personnel have been prohibited from traveling outside of the Khartoum/Omdurman/Bahri metropolitan area through April 19.
"I just arrived late last night in Khartoum and woke up to the deeply disturbing sounds of gunfire and fighting. I am currently sheltering in place with the Embassy team, as Sudanese throughout Khartoum and elsewhere are doing," John Godfrey, the U.S. Ambassador to Sudan, said in a tweet Saturday.
"Escalation of tensions within the military component to direct fighting is extremely dangerous. I urgently call on senior military leaders to stop the fighting," Godfrey said.