She screamed and people helped her escape with her six children.

Flood waters have displaced more than one million people in and around Maiduguri, the capital of Borno State, in one of the worst ever floods in Africa's most populous country.

Thousands of homes were engulfed by rapidly rising waters after a dam burst following a weekend of torrential rain in northeastern Nigeria.

"I shouted for help in terror and some men outside heard my scream and came into the house which was already flooded and rescued us," said Yakubu, 26, describing her survival as a "miracle".

She and her children took shelter in one of the eight camps set up by authorities.

Barkindo Mohammed, the director general of Borno State Emergency Management Agency (SEMA), told AFP that the number of people displaced by the flooding could reach one million people.

Mohammed Sheriff, 60, was not so lucky. He too awoke in the middle of the night to rising waters in his home.

Together with his two wives, they carried six of their children, thinking that the two eldest, aged 11 and 13, would be strong enough to fight the current. The two children are still missing.

"We haven't seen them since and we fear the worst," Sheriff told AFP.

The National Emergency Management Agency (NEMA) said on Wednesday that at least 30 people have died in the floods -- the worst in 30 years, according to the United Nations refugee agency in Nigeria.

- Hunger and disease -

NEMA's director general Zubaida Umar said on X on Thursday she was relieved that the "flood level in Maiduguri is receding, and normalcy is beginning to return to the metropolis," adding that rescue operations were ongoing in the city flooded up to 40 percent.

"Children and families are still trapped in their homes," British charity Save The Children said in a statement on Friday.

"The immense damage to water and sanitation services is driving up the risk of cholera and other water- and vector-borne diseases," the NGO said, pointing out that the city's two main hospitals had also been flooded.

The World Food Programme (WFP) said the disaster would increase the risk of food insecurity, particularly in the vulnerable northeast.

At least 259 people have been killed by flooding in Nigeria since the beginning of the rainy season, according to Umar.