A heavy hailstorm pounded the capital Mexico City leading to a partial collapse of the roof over the most important Aztec temple in the city.

The modern roof, made of metal and acrylic panels, was installed to protect the ancient ruins underneath. The incident occurred just one day after the capital's archaeological zone reopened from COVID-19 pandemic closures.

The extent of damage on Wednesday to the famed Templo Mayor in the city's historic zone was not immediately clear, though archaeologists said it was not severe.

"Despite the spectacular nature of the accident, the damage to the archaeological heritage is not great," said Leonardo Lopez Lujan, director of the Templo Mayor Project.

One person was injured but did not need hospitalization after the structure's partial collapse in the torrential storm, according to a local administrative office.

Images circulating on social media showed soldiers guarding the taped-off area where the roof, along with a part of the site's fence, had been damaged.

Built and rebuilt throughout the 14th and 15th centuries, Templo Mayor was the sacred heart of the Aztec capital and believed to be the site of many human sacrifices.

The vast religious building was destroyed when the Spanish conquistadors razed Tenochtitlan in 1521 and rebuilt a colonial city on top of it.

Archaeologists first uncovered the temple in 1914, but the ruins were not excavated in earnest until the 1970s.

The historic center of Mexico City was named a UNESCO heritage site in 1987.