Artillery fire has pounded the outer areas of the Sudanese capital, Khartoum, as fighting that trapped civilians in a humanitarian crisis and displaced more than one million people entered its sixth week.

Air attacks were also reported on Saturday by witnesses in southern Omdurman and Khartoum North, the two cities that lie across the Nile from Khartoum, forming Sudan’s “triple capital”. Some of the attacks took place near the state broadcaster in Omdurman, witnesses said.

“We faced heavy artillery fire early this morning, the whole house was shaking,” said Sanaa Hassan, 33, who lives in the al-Salha neighbourhood of Omdurman. “It was terrifying, everyone was lying under their beds. What’s happening is a nightmare.”