He pointed to the Taliban’s acceptance of a three-day ceasefire offered recently by President Ashraf Ghani.
Although the Taliban turned down a chance to extend the halt, Mattis pointed to the way Taliban fighters joined with government security forces and civilians to break fast on the Eid religious holiday.
“Clearly Ghani has hit a responsive chord,” Mattis told reporters.
“Not just on the Afghan national government side, but also it cut deep into the Taliban. We’ll see how this goes forward.”
During the unprecedented ceasefire fighters on both sides of the conflict expressed hopes it would continue.
But the sight of its fighters openly mingling with security forces and civilians appeared to alarm the Taliban’s leaders, who ordered their men back to their posts.