LAGOS (Reuters) -- A fire at Nigeria's main airport injured six firefighters, delayed flights and caused passenger chaos after the power company cut electricity due to unpaid bills, officials said on Friday.

Flights were suspended for several hours after Thursday's power cut and fire, but airport workers said on Friday the control tower was working despite continued power outages and there were still delays to international flights.

Airlines had to check in passengers manually and luggage was transported by hand while thousands of hot and sweaty passengers crowded the departure hall. Toilets and stairways were in pitch darkness with only dim light elsewhere, witnesses said.

The National Electric Power Authority's (NEPA) cut electricity at Murtala Muhammed International Airport, the main arrival point to Africa's most populous country, early on Thursday for non-payment of bills. "NEPA cut off the power. When they brought it back, there was an explosion," said a fire service official who declined to be named. "There was a surge from the current, which caused an explosion in the generator."

Airport workers said six firefighters were taken to hospital after inhaling noxious fumes from the blaze.

The official said firefighters eventually put out the blaze, but he could not say how bad the damage to the airport was.