By Paul Wood
Defence correspondent, BBC News
Investigations are continuing after a Nimrod plane crashed, killing 14 UK military personnel. The plane was lost during an ongoing offensive in southern Afghanistan.
Nato forces need the support of ordinary Afghans
Taleban guerrillas hanged a man from a tree in southern Afghanistan over the weekend, accusing him of spying for Nato.
At the same time, Nato said it had killed 200 Taleban fighters in Operation Medusa, an offensive which has been taking place since Saturday.
These two pieces of news encapsulate the problem for Nato in Afghanistan. Well-equipped conventional forces will always beat insurgents in a straight fight - but a straight fight is not always what's on offer from the Taleban.
The man was hanged in Helmand province. It is now home to thousands of British troops. Yet the Taleban had still set up their own "court" which found him guilty of spying for the "coalition and the infidel government".
Weeks earlier a 70-year-old woman and her 13-year-old grandson were hanged in Helmand province in a similar fashion.
Nato's big victories on the battle field will start to look a little hollow if the Taleban are able to continue to move around at will in the south, striking fear into the local population.
If anything, the mystery is why the Taleban seem so often to choose direct confrontation with Nato.
British commanders say the insurgents are reckless, often committing large groups of fighters in exposed positions, where they can be more easily targeted.
Nato believes that close on 1,000 militants have died in a summer of fighting.
The risk is, however, that Operation Medusa could simply push the Taleban out of the south to other parts of Afghanistan, or force them to hide, the most obvious tactic for a guerrilla army.
In the battle against the Taleban, the support of ordinary Afghans is therefore of paramount importance. Nato said that for all the heavy firepower employed over the weekend, there were no civilian casualties.
The Afghan defence ministry disagreed, saying that civilians had indeed been killed.
Earlier this year, in Helmand province, British troops were at risk of being over-run by the Taleban in a place called Nowzad.
They called in an American air strike. Our local freelance reporter questioned the villagers. They said the bomb had hit a market, killing civilians. Whether true or not, if such things are believed Afghanistan will start to look more and more like Iraq.
Nato has an additional problem in Afghanistan. It is that western soldiers are trying to fight the Taleban at the same time as backing the effort to destroy the opium trade, the main source of income for most of the country.
In practice, British soldiers are ignoring the opium problem for the time-being. They have a war to fight.
Combating the opium trade is a future problem to address
But later on, what will happen if an Afghan ally against the Taleban also turns out to be the local drugs baron? Given the immense official corruption brought to Afghanistan by drugs money, such dilemmas are inevitable.
Earlier this year, military commanders admit, the Taleban seized the initiative. The guerrillas threatened or actually seized towns like Panjwayi, in Kandahar province, and Sangeen, Musa Qaleh and Nowzad in Helmand. Now Nato is fighting back.
The rules of engagement for the British troops haven't changed. But defence sources say they are being interpreted much more aggressively, in order to carry out pre-emptive strikes on Taleban bases.
The British general who commands Nato in Afghanistan says the alliance has only the next six months to demonstrate that the Afghan government has backed the winning side.
The current, high tempo of operations can therefore be expected to continue; so too the level of casualties on both sides.
Nato is confident that the Taleban cannot sustain the current high rate of attrition. Senior commanders believe the sacrifices so far will bring victory in Afghanistan.