At least 10,000 people have been made homeless in the southern Democratic Republic of Congo after flash floods caused a river to burst its banks, killing dozens and laying waste to entire towns and villages.

In Boma, one of the worst-hit towns, residents told Al Jazeera they watched in despair as their loved ones were swept away by surging waters.

Makiadi Mvubu, who lost one of his daughters to the floods, told Al Jazeera: "I was trying to get into the house but just before I could it collapsed.

"We saved everyone but our daughter. We found her body four kilometres away."

Torrential rains caused the Kalamu river, which flows through Boma, some 470km southwest of the capital, Kinshasa, to overflow last month, causing waters to hit a peak of two metres above their average level.

Al Jazeera's Fahmida Miller, reporting from Boma, said some family members were still searching for bodies that may be buried in the mud.

"The force of the floodwater washed away a bridge," she said. "It was so strong that some bodies were swept 35km into neighbouring Angola."

So far, 50 people have been confirmed dead.

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Anger has surged in the past few days at the government's alleged slow response to the disaster.

"I am very disappointed because there is no help," Vundula Mwaka, a Boma resident who has lost his home twice in one year to flooding, told Al Jazeera.

"We have lost everything. I got injured and I still haven't been treated until now, not even a painkiller."

Emergency services have been accused of being poorly equipped to deal with natural disasters, especially with towns and cities typically built up in a haphazard fashion.

Despite its vast mineral wealth, the DRC is classed among the world's poorest countries and two thirds of its 70 million inhabitants get by on less than $1.25 a day.