Electricity is being restored in most parts of Kenya, 14 hours after the longest outage in recent memory.

There was still no clear explanation for the outage that began on Friday night, shutting down the country’s main international airport, affecting major hospitals and even disrupting the presidential office compound.

Transport minister Kipchumba Murkomen said in a statement: “I am really sorry for what has happened.

“There is no excuse worth reporting and there is no reason why our airport is in darkness.”

The majority government-owned power distributor Kenya Power said later on Saturday that it had restored service in most areas.

The outage came just weeks before Kenya’s government hosts the first Africa Climate Summit, where energy will be key on the agenda.

Kenya gets almost all its energy from renewable sources, but infrastructure and alleged mismanagement remain an issue in the country of more than 50 million people.

Kenya Power had announced in a brief statement that a “system disturbance” led to the loss of the bulk power supply to parts of the country just before 10pm on Friday.

Shortly after midnight, it reported that power had been restored to the Mt Kenya region, and added that initial reports indicated a fault in a generation plant.

Around 3am, Kenya Power said electricity was back up at the international airport in the capital, Nairobi, and other “critical areas” in the capital region.

However, three of Nairobi’s largest hospitals as well as the State House, the site of President William Ruto’s office, told The Associated Press they were still using generators earlier on Saturday.

The power outage had lasted for about 14 hours in what Kenyans called the longest blackout in memory. Calls to Kenya Power’s communications department did not go through.

Tourism is an important part of Kenya’s economy, and stranded travellers quickly posted images on social media of the darkened airport.

The Kenya Airports Authority said a generator serving the main terminal had failed to start after the national power outage.

Meanwhile, Kenyans already coping with rising cost of living woke up to find food spoiling and some back-up power options running out.

The most recent national power outage was in May.