Mexico City, Jan 10 (IANS): The Mexican military said on Tuesday that marines manning a highway checkpoint discovered nearly $1 million in cash hidden on a bus.

The seizure was made on Sunday in the northern state of Tamaulipas during an inspection, Efe news agency reported.

The bus was headed south from Reynosa, just across the border from McAllen, Texas, to the central Mexican city of Puebla.

After noticing "irregularities in the internal structure of the bus", the marines brought in sniffer dogs that led them to 43 plastic packages containing a total of $981,140, the navy said in a statement.

Once the cash was discovered, the bus driver and his assistant admitted that they had been paid to deliver the money to Puebla.

The marines turned over the suspects, the cash and the bus to the Attorney General's Office.

Mexico's drug cartels have taken to using intercity buses to smuggle their product to the US border and carry the proceeds from sales.