Electricity has been restored in Nigeria after the grid collapsed earlier on Monday for the sixth time this year.

The state-owned power distribution company said the outage was caused by a fire outbreak at the power station in Afam town in the southern Rivers state.

The system was restored later on Monday afternoon, the Transmission Company of Nigeria (TCN) said, adding that it would continue to strengthen the grid infrastructure to prevent future disruptions.

It is not clear how many people were affected, but there were angry comments across social media.

Grid power supplies are often erratic in Nigeria, despite being one of the biggest crude oil producers on the continent.