Chinese authorities say three men died when they suffocated while trying to rob an ancient tomb in the central province of Henan, known for its many relic-laden graves.

Yiyang county police said Monday that five villagers had entered a chamber of the tomb near their village of Chengjiao when three of them fainted from a lack of air.

They say the other two men called for help but attempts to rescue the three failed.

Police say one more man fainted during the rescue but was resuscitated, while the fifth tomb raider fled.

Both men were detained. They did not say what caused the lack of air in the tomb.

Known as a cradle of Chinese civilization, Henan is famous for the relics buried under its villages.