Seven worshippers killed in Nigeria mosque collapse

"Twenty-three persons were affected and evacuated to the hospital by our fire servicemen," the state Emergency Management Agency said on Friday. 

State officials said the mosque was constructed in the 1830s.

Videos apparently recorded at the scene showed a wide opening where a part of the roof fell in.

The victims were buried while prayers were held for them at the mosque.

Kaduna Governor Uba Sani ordered an immediate investigation into the disaster and promised to assist those affected by the "heartbreaking incident".

His officie said an advance team was already in Zaria.

The mosque's collapse comes after more than a dozen building failures in the West African nation in the last year. Authorities often blame such disasters on a failure by officials to enforce building safety regulations and on poor maintenance.