Washington (CNN) -- U.S. military operations in Afghanistan could continue to be fully supplied even if Pakistan refuses to open a major border post blocking hundreds of fuel tankers, the Pentagon said Tuesday.
But the United States is hoping to resolve the matter and reopen the route soon.
"We have been given indications that we are making progress on that front and hope to have the gate reopened as soon as possible," said Pentagon spokesman Geoff Morrell.
The pending decisions comes as NATO prepares to release a report on its investigation into a recent a deadly skirmish on the Pakistan-Afghanistan border. That incident, in which three Pakistan Frontier Corps soldiers were killed after firing on a NATO helicopter, is the latest pressure point in relations between the two countries.
After that border violence, the Pakistani government closed Torkham gate, the traditional Khyber Pass crossing between Pakistan and Afghanistan and a major supply route for U.S. forces.
Video: Making progress on supply route
The United States claims that a separate, more southern route through Pakistan, and other routes into northern Afghanistan will allow enough fuel and other supplies to be brought in to support U.S. and NATO operations.
"It has not in any way impacted our ability to resupply fuel to our operations around Afghanistan," Morrell said at a briefing Tuesday. "And we don't suspect it will even if this were to last into the future."
Morrell said that despite tensions, the U.S. military continues to work closely with its Pakistani counterparts.
"There are mistakes. There are incidents which create misunderstandings. There are setbacks," Morrell said. "But that does not mean the relationship -- this crucial relationship to us -- is in any way derailed."
Morrell said the formal report on the joint investigation into the border incident will be released Wednesday morning in Kabul.
"Obviously, there was an unfortunate incident in which it looks as though, I think it was, three (Pakistan) Frontier Corps soldiers were killed as one of our helicopters was investigating what looked to be a new fighting position that was being erected along the border that posed a potential threat to our forces in Afghanistan," Morrell said. "And I guess they came under fire while they were checking out that position."
The United States and NATO are making efforts at military and diplomatic levels to apologize to Pakistan for the border clash. At the same time, the Pentagon insists that U.S. and allied forces will defend themselves.
"We will retain the right to defend our forces, to defend ourselves." Morrell said. "Our forces who operate on the border with Pakistan are in a very dangerous and difficult situation."
He said the United States hopes for a quick reopening of the border crossing, but the delays and recent attacks on fuel convoys are not hampering U.S. operations. Pakistan itself would benefit from reopening the border, he suggested.
"This is a huge commercial enterprise for them and they do not get paid until that fuel is delivered to the point of destination in Afghanistan," Morrell said about Pakistani fuel shippers. "So they have incentive to protect the convoys, to make sure that the situation is such that they can get to their destination safely."
The border closing by Pakistan and new attacks on fuel convoys have focused attention on both the supply routes through Pakistan and the ongoing discussions between the United States and Pakistan over whether Islamabad can do more to fight militants who take refuge along the Afghanistan-Pakistan border.
Morrell said that attacks on fuel convoys interrupt just a tiny fraction of U.S. war supplies.
"There have been attacks historically on NATO convoys passaging through Pakistan to Afghanistan. And they are sometimes sensational and they are sometimes horrific and they are sometimes deadly and that is tragic," Morrell said. "But if you put this in context and in perspective, we're talking about, you know, impacting about one percent of the supplies that we funnel through Pakistan into Afghanistan. So they have never really adversely impacted our ability to conduct operations in Afghanistan."
Some outside observers have scolded the Pentagon for depending too heavily on Pakistan shipping routes, concerned that it provides Pakistan with a way to subvert U.S. policies.
Heritage Foundation Senior Research Fellow Lisa Curtis says the United States must step up efforts to open more supply routes outside of Pakistan.
"Not only are the Pakistani supply routes increasingly under threat of militant attacks, the U.S. dependence on Pakistani supply routes provides Islamabad leverage to resist U.S. pressure to shut down Taliban sanctuaries and to crack down more forcefully on terrorist networks," Curtis said in a Heritage Foundation e-mail.
