But there are only anecdotal reports to help gauge just how deadly the offensive has been. The Afghan defense and interior ministries stopped releasing casualty data after a shocking surge of military and police deaths in 2013 began raising questions about the country’s ability to sustain the losses. By September, with more than 100 soldiers and police officers dying every week, even the commander of the International Security Assistance Force suggested the losses could not be sustained.

Asked for figures on the latest security force casualties this year, both ministries refused to provide data or confirm accounts from local officials. But there are signs that the casualty rate is already likely to be at least as bad as it was last year.

In one important indicator, the United Nations reported a 24 percent rise in civilian casualties for the first half of this year compared with a similar period from 2013, hitting a new peak since the United Nations Assistance Mission in Afghanistan began tracking the data in 2009. More significantly, for the first time, the highest number of those casualties came from ground fighting between the Afghan forces and insurgents rather than from roadside bombs.

The United Nations found that more fighting was taking place near populous areas, closer to the district centers that serve as the government seats. Ground violence also seemed to increase in areas where coalition bases had been closed, as the Taliban felt more emboldened to launch attacks without fear of reprisal.

One important effect of those gains, particularly where police forces are being driven away, is that the Taliban are establishing larger sections of lawless territory where they can intimidate local populations. They become safe havens, and staging grounds for more ambitious attacks against Kabul and other major cities, like the militant assault on Kabul’s airport on July 17.