JIM LEHRER: That follows our two Afghanistan stories.
We begin with the attack on British soldiers in Helmand Province.
Nick Paton Walsh of Independent Television News reports from Kabul.
NICK PATON WALSH: It was perhaps the worst afternoon they have had here at Camp Bastion since the war began. They save lives here daily, but seldom this many of their own countrymen, one single shooting claiming the lives of five British soldiers in an instant that could shake NATO's war strategy.
The helicopters kept on coming, six British soldiers and two Afghan police also badly wounded; 92 British troops have died this year, most from roadside bombs or gunfire. But this was different, shocking. These men were shot dead by a member of their own team they were meant to trust, an Afghan policeman.
LIEUTENANT COLONEL DAVID WAKEFIELD, British Army: They worked and lived there, they had done for the last two weeks, with Afghan national policemen. And it would appear that -- and this is, as I say, our initial understanding of what went on, is that an individual Afghan national policeman, possibly acting in conjunction with one other, started firing inside the checkpoint, before fleeing from the scene.
NICK PATON WALSH: The incident took place 400 meters from a British base in Nad-e-Ali. It was quarter past 3:00 after a joint foot patrol. The British trainers debriefed the Afghans, their body armor off, their weapons nearby.
On the roof, the gunman shot his Afghan commander, before aiming the AK-47 at the British. He then escaped on a motorbike into a Taliban stronghold.
Gordon Brown said the Taliban were behind the attack, and had infiltrated the Afghan police. A Taliban spokesman agreed, and said more such attacks would follow. And talk of tensions between the British and Afghans on the front line was met with a show of unity this afternoon.
BRIGADIER GENERAL MIRWAIS NOORZAI, policeman, Afghanistan: We have passed our sympathies to the families of the dead soldiers. Now we're here with the British general to show our commitment to the investigation and to the cooperative work we will do to establish exactly what happened.
MAJOR GENERAL NICK CARTER, British Army: Well, the first point I would make is that we have to trust the uniform of the Afghan police. And the second point I would make is that we will get better at this. And we will make it perfectly possible for us absolutely to understand who we're working with, because we will train them, and we will make sure that they're capable of doing the job in the way that they know they need to do the job.
NICK PATON WALSH: Tonight, locals reported gunfire in nearby villages, as troops searched for the gunman. Local sources have told Channel 4 News the gunman was called Gulbuddin, age 28. Ex-army, he had been in the police for two years and at the checkpoint for a few months.
It's not yet confirmed if he was working for the Taliban, or settling a grudge, or looking for tribal prestige. Afghan police are trained quickly. NATO wants to hugely increase their number. There are fears that bad recruiting is taking corruption in their ranks to new heights.