Archaeologists in Egypt have discovered a 4,300-year-old pyramid under the sands of Saqqara not far from the capital, Cairo.

Zahi Hawass, the country's antiquities chief, said that a largely unexplored burial site lies at Saqqara, much of it buried deep below the sand.

A number of pyramids have been unearthed at the site, which lies about 19km south of the better known pyramids of Giza.

The burial chamber is thought to have belonged to the queen mother of the founder of Egypt's 6th dynasty, several hundred years after the building of the Great Pyramids of Giza, Hawass said as he showed reporters around the site on Tuesday.

"To find a new pyramid is always exciting," Hawass said. "And this one is magical. It belonged to a queen."

The discovery is part of a sprawling burial site, or necropolis, for the rulers of ancient Memphis, the capital of Egypt's old kingdom.

The remains include a square-shaped 16ft-tall structure which had been buried under 65ft of sand.

Hawass said: "There was so much sand dumped here that no one had any idea there was something buried underneath."

Hawass' team has been excavating at the location for two years. Just two months ago they determined the structure, with sides about 72ft long, was the base of a pyramid.

They also found parts of the pyramid's white limestone casing - believed to have once covered the structure - which enabled them to calculate that the complete pyramid was once 45ft high.

The pyramid is the 118th discovered in Egypt.

Hawass said he believes the pyramid belonged to Queen Sesheshet, who is thought to have played a significant role in establishing the 6th dynasty and in uniting two branches of the feuding royal family.

Her son, Teti, is thought to have ruled for about 20 years until he was assassinated, a sign of the time's turbulence.