Power was restored to parts of Liberia's dilapidated capital Monrovia for the first time in 15 years on Wednesday, but the celebrations were cut short when the executive mansion caught fire with four presidents inside.
The leaders of Ghana, Ivory Coast and Sierra Leone were guests of President Ellen Johnson-Sirleaf to celebrate the restoration of mains electricity, a symbolic step in Liberia's emergence from 14 years of civil war, when the fire broke out.
"I was on the sixth floor serving the president water when it was announced there was a fire in the building. Immediately the president and the others had to run down the stairs," said a worker in the building, who gave her name as Estella.
Heads of state and diplomats decamped to Johnson-Sirleaf's private residence. A senior police officer said the cause of the blaze was unclear but investigations were underway.
Looting during Liberia's conflict, which ended in 2003, shattered the West African country's infrastructure. Power cables were torn down and water pipes ripped up for scrap metal by fighters, many of them child soldiers high on drugs.
Johnson-Sirleaf earlier flicked a switch draped in a Liberian flag to turn on the lights around a suburban clinic, prompting cheering from watching residents. Children who had never seen street lights illuminated watched in wonder.
Johnson-Sirleaf, Africa's first elected female head of state, promised when she took office in January that she would work to restore power to the seaside capital within 150 days.
It seemed a bold promise for the city, a hotchpotch of moss-covered ruins and shantytowns whose wealthier districts hum to the sound of fuel-powered private generators while its poorer quarters are plunged into darkness each night.
Foreign donors struggled to help even after the war ended: technical assistance failed when equipment was looted and aid funds went astray at the hands of the corrupt transitional government that preceded Johnson-Sirleaf's election.
Liberia's war was one of the most brutal in modern African history, killing a quarter of a million people and ending when warlord and President Charles Taylor - now in The Hague on war crimes charges - fled to exile in Nigeria.