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Watch: Sheltering from fighter jets and gunfire around Khartoum airport
The fighting that has erupted in the Sudanese capital, Khartoum, and elsewhere in the country is a direct result of a vicious power struggle within the country's military leadership.
The clashes are between the regular army and a paramilitary force called the Rapid Support Forces (RSF).
Sudan is in north-east Africa and is one of the largest countries on the continent, covering 1.9 million square kilometres.
It is also one the poorest countries in the world, with its 46 million people living on an average annual income of $750 (£606) a head.
The population of Sudan is predominantly Muslim and the country's official languages are Arabic and English.
Since the 2021 coup, Sudan has been run by a council of generals, led by the two military men at the centre of this dispute:
They have disagreed on the direction the country is going in and the proposed move towards civilian rule.
The main sticking points are plans to include the 100,000-strong RSF into the army, and who would then lead the new force.
The violence follows days of tension as members of the RSF were redeployed around the country last week in a move that the army saw as a threat.
There had been some hope that talks could resolve the situation but these never happened.
It is disputed who fired the first shot on Saturday morning but fighting has since escalated in different parts of the country with almost 100 civilians dying, according to a Sudanese doctors' union.
Even though the conflict appears to be around the control of key installations, much of it is happening in urban areas and civilians have become the unwitting victims.
It is not exactly clear where the RSF bases are, but it seems that their fighters have moved into densely populated areas.
The Sudanese air force has mounted air strikes in the capital, a city of more than six million people, which is likely to have led to civilian casualties.
There was a brief pause in the fighting on Sunday, agreed by both sides, to allow people to escape the fighting.
The RSF was formed in 2013 and has its origins in the notorious Janjaweed militia that brutally fought rebels in Darfur, where they were accused of ethnic cleansing.
Since then, Gen Dagalo has built a powerful force that has intervened in conflicts in Yemen and Libya. He has also developed economic interests including controlling some of Sudan's gold mines.
The RSF has been accused of human rights abuses, including the massacre of more than 120 protesters in June 2019.
Such a strong force outside the army has been seen as a source of instability in the country.
This fighting is the latest episode in bouts of tension that followed the ousting of long-serving President Omar al-Bashir in 2019.
There were huge street protests calling for an end to his near-three decade rule and the army mounted a coup to get rid of him.
But civilians continued to campaign for a return to democratic rule.
A joint military-civilian government was then established but that was overthrown in another coup in October 2021, when Gen Burham took over.
And since then the rivalry between he and Gen Dagalo has intensified.
A framework deal to put power back in the hands of civilians was agreed last December but talks to finalise the details have failed.
Gen Dagalo has said that the 2021 coup was a mistake and has tried to present himself and the RSF as being on the side of the people, against the Khartoum elites.
While he has some support, others find this message hard to believe given the paramilitary force's brutal track record.
Meanwhile, Gen Burhan has said the army will only fully hand over power to an elected government, further sidelining civilian representatives expected to be part of a power-sharing deal.
But there are suspicions that both military men, and their supporters, are worried what might happen to their wealth and influence if they are removed from their powerful positions.
There are fears that the fighting could further fragment the country, worsen political turbulence and draw in neighbouring states.
Diplomats, who have played a crucial role in trying to urge a return to civilian rule, are desperately trying to find a way to get the two generals to talk.
A regional bloc agreed to send three presidents – from Kenya, South Sudan and Djibouti – to Khartoum, but it is unclear if they can make the trip as no planes are flying in or out of the country.
The UK, US and EU have all called for a ceasefire and talks to resolve the crisis.
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