Cocaine is susceptible to interdiction at sea or after it is imported into Mexico before it is distributed in smaller packages for onward transport. Subsequently, land interdiction may still be possible at checkpoints if inspectors are trained, equipped and supervised properly. The Isthmus of Tehuantepec constitutes a natural chokepoint for land transportation. The area offers interdiction opportunities which do not exist anywhere else in Mexico. Over one hundred metric tons of cocaine that arrives in Central America and in southern Mexico pass through or around the Isthmus.