Human remains have been uncovered amid the debris of a firework warehouse, days after it caught fire and exploded, setting off a wild pyrotechnics display over California.

Seven people are still "unaccounted for" in Yolo County's town of Esparto after several explosions at a fireworks warehouse resulted in a fire, officials said.

Human remains were found inside a fireworks' storage warehouse in rural Yolo County, officials announced on Friday, three days after a massive explosion occurred inside the facility.