Hundreds of people have been killed in nearly two weeks of conflict between the army and a rival paramilitary force - the Rapid Support Forces (RSF) - which are locked in a power struggle threatening to destabilise the wider region.
An RSF statement accused the army of carrying out air strikes on its forces on Thursday and spreading "false rumours," making no reference to a proposal for peace talks which the army said came from a regional bloc known as the Intergovernmental Authority on Development (IGAD).
An army statement said its forces had taken control of most of the country's regions but added "the situation is a bit complicated in some parts of the capital," noting it was in the process of defeating what it called a large deployment of RSF.
The sound of air strikes and anti-aircraft fire could be heard in the capital Khartoum and the nearby cities of Omdurman and Bahri, witnesses and Reuters journalists said.
An existing three-day ceasefire brought about a partial lull in fighting but is due to expire at midnight.
Many foreigners remain stuck in Sudan while Sudanese civilians, who have been struggling to find food, water and fuel, continued to flee Khartoum on Thursday.
The army late on Wednesday said its leader, General Abdel Fattah al-Burhan, had given initial approval to the IGAD plan to extend the truce for another 72 hours and to send an army envoy to the South Sudan capital Juba for talks.
The military said the presidents of South Sudan, Kenya and Djibouti worked on a proposal that includes extending the truce and talks between the two forces, whose conflict derailed a transition to civilian democracy after a 2021 military coup.
IGAD reaffirmed an earlier call for an immediate cessation of hostilities, de-escalation and a return to the negotiating table.
A statement by the bloc made no mention of Juba talks.
Gamal Malik Ahmed Goraish, Charge d' Affaires at Sudan's embassy in Juba, told Reuters it was not clear how any talks would happen or what the agenda would be.
US Secretary of State Antony Blinken and African Union Commission Chairperson Moussa Faki Mahamat discussed working together to create a sustainable end to the fighting, the US State Department said on Wednesday.
At least 512 people have been killed and close to 4200 wounded by the fighting since April 15.
The crisis has sent growing numbers of refugees across Sudan's borders.
Thousands of people, mainly Sudanese, have been waiting at the border to cross north into Egypt.
About 16,000 people have entered Egypt from Sudan including 14,000 Sudanese citizens, the Egyptian foreign ministry said.
The United Nations says 20,000 refugees have already gone to Chad.
At International University of Africa in Khartoum, where thousands of students are waiting to leave, food is running out, there is no water for toilets and showers and the power is out, Nigerian law student Umar Yusuf Yaru said.
"Even as we sit here, almost everywhere you can hear gunshots. We are not safe here," Yaru said via Zoom as some female students could be heard crying in the background.
