A US citizen has been accused of trying to smuggle in four Chinese citizens....in his car trunk.

This bizarre version of human tetris was discovered by Customs and Border Protection officers at the US-Mexico border.

A CBP dog indicated there was something off about what looked like an empty Chrysler sedan, but when agents searched they found what they call, a human-smuggling attempt.

Inside the unnamed 24-year-old driver's trunk were three men and a woman, all Chinese nationals.

Authorities say the four do not have legal permission to enter the US, have since had an immigration hold placed on them and are expected to be deported.

The driver was taken into custody at the Metropolitan Correctional Center in San Diego.