Many of the victims of the attack, in the Kalakla al-Qubba neighbourhood of south-west Khartoum, have been buried in the rubble, they said.
Artillery and rocket fire have been reported in several areas on Sunday.
The army and the paramilitary Rapid Support Forces (RSF) have been fighting for control of Khartoum since April. Hundreds have been killed.
The country’s health ministry says more than 1,100 people have died across the country, but the real numbers are likely to be much higher.
Many civilians have been caught in the crossfire.
Roughly 2.2 million people have been displaced within Sudan and more than half a million are sheltering in neighbouring countries, according to the United Nations.
The conflict began after army chief Gen Abdel Fattah al-Burhan and the RSF head Gen Mohamed Hamdan Dagalo fell out over the future of the country.
Several ceasefires have been announced to allow people to escape the fighting but these have not been observed.
The RSF controls much of Khartoum and its twin cities of Omdurman and Bahri.
The army has carried out frequent artillery and air attacks to try and dislodge the paramilitary fighters.
Saturday’s strike is one of the heaviest.
Clashes have spread beyond the capital, including to the western Darfur region which has seen an outbreak of ethnic violence.
Across the country, hundreds have been killed and almost three million people have been forced from their homes.
