The World Health Organisation (WHO) is scaling up its emergency response in Congo-Brazzaville as the central African nation battles one of its worst floods in decades.

The UN health body has allocated $100,000 (£78,000) for the deployment of first responders, WHO's Africa office announced on Thursday.

"Heavy flooding has caused widespread devastation in Congo, with nine of its 12 [regional] departments affected," it said, adding that the floods have affected more than 336,000 Congolese, 34 health facilities and more than 2,200 hectares of farmland.

Congo Brazzaville and the neighbouring Democratic Republic of Congo are battling severe floods following heavy rains and the rising of water in the Congo River to the highest levels since 1961.

In DR Congo, the floods have killed more than 300 people and displaced over 300,000 households, Reuters news agency reports, citing the social affairs ministry.

Many factors contribute to flooding, but a warming atmosphere caused by climate change makes extreme rainfall more likely.