Sudan is waking up to a 72-hour ceasefire, which took effect at midnight on Monday.
It is at least the third suspension of fighting since violence erupted this month, but the others did not hold.
US Secretary of State Antony Blinken said an agreement had been reached between the army and the paramilitary Rapid Support Forces (RSF) after 48 hours of negotiations.
At least 400 people have been killed since fighting erupted on April 15.
Both sides in the conflict independently announced their involvement in the ceasefire
A ceasefire in Sudan appears to be holding, although there have been reports of new gunfire and shelling.
It is the fourth effort to stop the fighting which began on 15 April, with previous truces not observed.
US Secretary of State Antony Blinken said the 72-hour truce had been agreed between the army and the paramilitary Rapid Support Forces (RSF) after 48 hours of negotiations.
The latest ceasefire attempt started at midnight (22:00 GMT on Monday).
At least 459 people have died in the conflict so far, though the actual number is thought to be much higher.
Both sides had confirmed they would cease hostilities.
But Tagreed Abdin, who lives 7km from the centre of Khartoum, said she could hear shelling from her home on Tuesday morning despite the agreement.
“The situation right now is that this morning there was shelling and gunfire,” she told the BBC.
“Obviously the ceasefire hasn’t taken,” she added.
The RSF has accused the army of violating the truce by “continuing to attack Khartoum with planes”.
Meanwhile, an army spokesperson has told Sky News Arabia that the RSF was responsible for “storming prisons” following reports of gunfire at Port Sudan.
In other developments, the World Health Organization (WHO) has warned there is a “high risk of biological hazard” after fighters seized a laboratory believed to be holding samples of diseases including polio and measles.