MEXICO CITY -- State officials say inmates rioted at a psychiatric block in a prison in northern Mexico, broke into a prison pharmacy and took drugs that caused the deaths of two of them.

Thirteen more were injured in Tuesday's riot, including one guard.

The complex chain of events at the prison in Cadereyta, in Nuevo Leon state, started earlier this week when inmates protested a new program to inspect visitors with a type of X-ray machine to prevent contraband being smuggled into the facility.

That caused a smaller disturbance Monday.

But on Tuesday the state security spokesman said about 56 inmates at a psychiatric block burned about 200 cells and furnishings. Some then broke into the prison pharmacy, where two of them overdosed on medications stored there.