The National Immigration Institute said today that the attackers riddled the agents' vehicles with 61 rounds from at least three different guns.
The attack was carried out by five men on motorcycles.
The attackers managed to grab the 25 migrants the agents had detained earlier at a checkpoint, and also freed a suspected migrant trafficker.
They made off in the truck they had originally been transporting the migrants in. Both agents wounded in the attack have recovered and returned to duty.