Back in July, Pakistan finally re-opened its highways to NATO supply trucks after the routes had been closed for several months in response to the US killing 24 Pakistani soldiers in an attack on a border post in November, 2011. A huge backlog of trucks and supplies had accumulated during that prolonged closure, and clearing it was complicated by the resumption of attacks on the supply convoys inside Pakistan.

On Saturday, the Wall Street Journal informed us that the US would test using the Pakistan overland route in reverse, as the long process of ending the NATO mission in Afghanistan by the end of 2014 begins its withdrawal of equipment:

The U.S. military’s efforts to ship out the mountains of equipment it accumulated over 11 years of Afghan war began in earnest this month, when a trial load of military hardware trucked through Pakistan set sail from the port of Karachi.

The shipment, which included more than 70 containers and 20 military vehicles, was a crucial test of a plan to bring home an estimated $22 billion in U.S. military gear from landlocked Afghanistan. Until now, the Pakistani route was used for supplies entering Afghanistan, rather than exiting.

U.S. Army Brig. Gen. Steven Shapiro, deputy commanding general of the 1st Theater Sustainment Command, said the successful delivery proved that the coalition’s transit route through Pakistan would enable the military to meet President Barack Obama‘s goal of cutting the size of the 66,000-strong American force in Afghanistan by half by next February.

“Pakistan certainly has a vested interest in getting it right too, because it’s a big deal for them,” Gen. Shapiro said. “So we feel very confident that the Pakistani military is going to help us move through Pakistan.”

Perhaps that first shipment of 20 trucks made it through, but today we have news that a convoy of five trucks on the exit route was attacked and destroyed. From AFP via the Express Tribune:

Five trucks carrying Nato equipment out of Afghanistan were set ablaze by gunmen near Quetta on Monday, as the international military alliance winds down its combat mission there, officials said.

Four masked gunmen on two motorbikes opened fire at the vehicles, forcing them to stop and then doused them in petrol to set them on fire in Balochistan.

“Five Nato trucks were carrying Nato equipment back. Gunmen first fired on the first vehicle and then sprinkled petrol on all of them,” Iftikhar Bugti, a senior government official told AFP by telephone.

The incident happened in Bolan district, around 120 kilometres (75 miles) southeast of Quetta, the provincial capital.

“All five trucks have been almost completely destroyed,” Bugti said. One driver was slightly injured in the attack, he added.

The pace of exiting material is expected to pick up greatly, and the Wall Street Journal article informs us that the bulk of the material will be shipped through Pakistan:

When the exodus is in full swing—military commanders expect the logistics push to reach its peak this August—the U.S. will be sending about 1,500 military vehicles and 1,000 containers per month out of Afghanistan. The majority—around two-thirds of that cargo—will move through Pakistan, military officials say.

The most sensitive equipment, such as weapons and communications systems, must be flown out by air, the costliest option. U.S. officials have also negotiated an alternative overland route, dubbed the Northern Distribution Network, through Central Asia to Baltic and Black Sea ports. While more expensive than the route through Pakistan, the NDN isn’t exposed to attacks by Pakistani Taliban.

Perhaps the military will be content to allow a number of the convoys to be burned by militants in Pakistan. After all, when the military burns excess equipment, it now has to track the soldiers who were at the burn site for future health problems.