Firefighters spray water on the National Museum of Brazil after a fire burnt it in Rio de Janeiro. Ricardo Moraes/REUTERS.

Rio de Janeiro - One of the oldest skeletons ever found in the Americas may have survived the blaze that devastated the National Museum of Brazil in Rio de Janeiro, the newspaper O Globo reported Tuesday.

A firefighter who did not give his name said he had found a skull inside an iron chest. The 11 000-year-old skeleton known as Luzia Woman had been inside a chest, museum sources had said earlier.

The museum called for caution until the identity of the skull had been confirmed.

The army meanwhile surrounded the building to prevent looting and to protect firefighters who were extinguishing a few remaining pockets of the blaze, which started late Sunday, according to O Globo.

The museum's entire collection of about 20 million exhibit items was initially reported to have been destroyed, with the exception of meteorites, which are resistant to high temperatures.

But the museum's deputy director Cristiana Serejo said late Monday that 10% of the collection may have been spared.

However, the museum's Egyptian collection, which included mummies and counted among the most important on the continent, was entirely destroyed.

Television images showed almost all of the historic building, located in the city's Sao Cristovao locality, in flames on Sunday.

The building had served as a museum since 1892 and was formerly a residence of the Portuguese royal family and later of Brazil's imperial family.

The National Museum is the South American country's oldest museum and housed extensive geological, botanical, palaeontological and archaeological collections.