The temple is nestled inside the Teopanzolco pyramid in Morelos state, 70km (43 miles) south of Mexico City.

It is thought to date back to 1150 and to belong to the Tlahuica culture, one of the Aztec peoples living in central Mexico.

The structure is dedicated to Tláloc, the Aztec rain god.

Archaeologists say it would have measured 6m by 4m (20ft by 13ft). Among the temple's remains they also found an incense burner and ceramic shards.

The discovery was made when scientists from Mexico's National Institute of Anthropology and History (INAH) used a radar to check for structural damage to the Teopanzolco pyramid in Cuernavaca.

Archaeologist Barbara Koniecza said the 7.1-magnitude earthquake which hit Mexico in September caused considerable damage to Teopanzolco, in particular to two temples

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• Mexico earthquake as it struck

"The pyramid suffered considerable rearrangement of the core of its structure," Ms Koniecza said.

Research suggests that the Tlahuica lived in dozens of small city-states in the area of modern-day Morelos state.

The main structures at the archaeological site of Teopanzolco are thought to date back to the 13th Century, which means that the newly discovered temple would have predated them.

Ms Koniecza says it was not unusual for the Tlahuica to build on top of older structures.