PHOENIX -- The border war is escalating, and drug smugglers are getting more sophisticated in their methods, agents from the U.S. Border Patrol said.

A recent drug smuggling attempt had smugglers using a large vehicle carrier as a ramp to drive two cars packed with marijuana over the border wall into the United States, agents said.

When border agents interrupted the operation, the two dozen smugglers started throwing the bundles of marijuana back over the border wall into Mexico.

Shots were fired, Molotov cocktails thrown and a vehicle torched before the smugglers crossed back into Mexico.

"When these people got out of their vehicle, the agents in the field said they were carrying weapons, handguns, assault rifles, things like that," said Border Patrol agent Mike Scioli.

Scioli also said the operation was notable because of how organized the smugglers were.

"This took 20 different smugglers, a vehicle carrier, ramps and … a foot guide walking these vehicles north to the highway," he said. "That's a lot of planning."

The Border Patrol's night vision technology helped agents stop the attempt, Scioli said.

"We had the ability to see what they were doing before they were even at the fence," he said.

Agents have another new weapon to combat smuggling -- an all-terrain vehicle made out off 30,000 pounds of bullet-proof, bomb-proof steel.

Additionally, many of the patrol's vehicles surrounded by steel cages to protect agents from rocks hurled at them -- a practice known as "rocking" among the ranks. One agent died after being hit by a stone.

"(Smugglers will) 'rock' our agents, and while they're being distracted, that's when they move," Scioli said. "They move drugs, they move human traffic."

Besides rocks and guns, the smugglers have a large arsenal of weapons and attack plans. In fact, only nine of the 261 attacks in the past year involved guns; the others involved throwing rocks, physical attacks and using a car as a weapon.