Attacks against U.S. and NATO forces in Afghanistan are escalating, fueled in part, U.S. officials say, by al-Qaida and Taliban militants in Pakistan, who easily cross the border into Afghanistan to join the fight.
So NBC News decided to investigate security at one of Pakistan's busiest border crossings. Two NBC News producers bought tickets for $4 each and boarded a bus in Pakistan, destination Jalalabad, Afghanistan. The route took them from Peshawar, through a major border checkpoint, to Jalalabad.
Their bus full of passengers was waved through the border crossing. Not once in four hours did Pakistani or Afghan guards stop them or check for travel documents.
"Nobody asked us (for) our documents," says producer Iqbal Sapand. "Not only me, there were more than 45 people in that bus."
The next day our producers repeated the process, taking the bus from Afghanistan back to Pakistan. Again, no documents necessary.
"On both sides of the border, nobody checked them," says NBC's Mushtaq Yusufzai.
Locals told NBC it's always this way. One man says he sometimes has a problem if he crosses the border on foot, but never a problem on the bus.
Pakistan's Ambassador to the U.S., Mahmud Ali Durrani, says the sheer volume of cross-border traffic makes it difficult to patrol. He says 200,000 people cross the border every day and it's not possible to check everyone.
"Even if there are about 15 or 20,000 people crossing sides, it's almost impossible with the present set up," he says. "We are trying to get there. We need help, and right now it's far from perfect."
Durrani also believes his country is carrying the bulk of the responsibility for border patrol, counting over 1,000 border posts on the Pakistan side, as opposed to around 100 on the Afghan side.
"I think we are doing much more than the other side," he says. "Why do we have to be responsible for everything? Why not the other side, too? I'm not saying this is a good system, but we are trying our best and we are facing opposition."
Pakistani President Pervez Musharraf also is walking a tightrope between domestic political pressures and increased U.S. demands for tighter security.
"If you can't secure the front door to Afghanistan, how can you have any confidence that Pakistan is securing the back door, such as the tribal area where we know al-Qaida is operating right now?" asks NBC News terrorism analyst Roger Cressey.
In fact, militants need not brave the elements and inhospitable mountain terrain to reach Afghanistan — for $4 they can take the bus.