At least 170 people have died and more than 200,000 others are displaced following weeks of flooding in Africa’s most populous country, a spokesperson for Nigeria’s disaster management agency told CNN Tuesday.

Northern Nigeria has been hit hardest by the floods, according to Manzo Ezekiel, who speaks for the National Emergency Management Authority (NEMA). Other parts of the country however remain at risk, he added, amid torrential rains and the rising water levels of its two largest rivers — the Niger and the Benue.

“The pattern of flooding in Nigeria is such that it usually happens on the northern side before moving to the central and the southern parts… because the water flows downwards,” Ezekiel said. “In the coming days, the central parts will soon witness similar floods, and even downwards to the southern parts.”

Although parts of Nigeria are prone to floods during the rainy season, Ezekiel said this year’s flooding has been reported in areas where it had previously been rare.

“The situation is such that some places that were not previously known to be prone to floods are experiencing floods this time because of climate change,” he told CNN.

Environmentalists partly blame the country’s annual floods on poor drainage infrastructure.