ABUJA, Nigeria (AP) — A dam collapsed Tuesday in northeastern Nigeria unleashing severe flooding that prompted evacuations and swept deadly reptiles from a zoo into communities in the area, local officials and a zoo manager said.

The collapse of the Alau dam in the state of Borno caused some of the state's worst flooding since the same dam collapsed 30 years ago, and prompted many residents to flee their homes. The dam was at full capacity due to unusually high rains, according to the state government.

About 15% of the Borno state capital Maiduguri was under water, Nahum Daso, the state’s police spokesperson told The Associated Press. No death toll from the flooding has been released yet.

At the Borno State Museum Park, the flooding killed about 80% of the animals while an unspecified number of reptiles escaped, zoo general manager Ali Abatcha Don Best said.

“Some deadly animals have been washed away into our communities, animals like crocodiles and snakes,” the zoo manager said.

The local authorities issued a flooding alert and an immediate evacuation order for residents close to river banks, Usman Tar, Borno’s commissioner for information and internal security said. All schools in the state will close for the next two weeks, he added.

The dam collapse is compounding a humanitarian crisis in Borno over the past decade due to the activities of Boko Haram insurgents. The insurgency, which has spilled across borders around Lake Chad, has killed more than 35,000 people, displaced 2.6 million others in the country’s north-east region.

Boko Haram, with one branch allied to the Islamic State group, wants to install an Islamic state in Nigeria, West Africa’s oil giant of 170 million people divided almost equally between a mainly Christian south and a predominantly Muslim north.

Earlier this year, at least 18 people were killed by suicide bombers in a coordinated attack targeting a wedding, a funeral and a hospital in Borno.