Police in Nigeria say seven people are dead after a live electrical wire fell onto a gathering of people watching football, but residents say the death toll is higher.

Cross River state police spokeswoman Irene Ugbo says another 10 people are critically injured after the wire fell on the roof of a football viewing center in Calabar on Thursday night.

Resident Ukeme Joseph puts the death toll at 20 instead, saying more than 80 people were crammed inside at the time.

The Port Harcourt Electricity Distribution Company has not commented on the incident, but authorities have said it is illegal to erect structures under high-tension cables.

Many Nigerians prefer to watch football games at the viewing centers instead of at home.