BEIJING, Aug. 2 (Xinhuanet) -- Construction workers in June unearthed ancient walls in the crime-infested Iztapalapa district of Mexico City and now archaelogists have discovered what they believe are ruins of an Aztec pyramid razed by Spanish conquistadors.

Government archaeologists said on Wednesday they think the walls may be part of the main pyramid of the Aztec city, destroyed by troops commanded by Hernan Cortes in the 16th century.

Iztapalapa, now infamous for violent crime and drug dealing, has grown into a sprawling, poor district of the capital, obscuring the ruins.

"We knew the general location but couldn't explore because it's a big urban area," said archeologist Jesus Sanchez, site director.

Iztapalapa's ruler, Cuitlahuac, nearly annihilated Cortes and his Spanish troops in 1520 in what became known as the Sad Night. After eventual victory, Cortes destroyed the city.

Sanchez hopes he has found the city's main pyramid just below the neighborhood's central plaza and garden. He and his team will spend more than a year investigating before deciding whether to excavate.

Pre-Hispanic ruins abound in Mexico City. In October, archaeologists in the city's central Zocalo Square unearthed a 15th-century Aztec altar and a 12-ton stone idol just yards from downtown traffic.

The Aztecs, a warlike and deeply religious people who built monumental works, ruled an empire stretching from the Gulf of Mexico to the Pacific Ocean and encompassing much of modern-day central Mexico.

(Agencies)