Abdullah described the growing desperation and brutality of a war he and his 150 men now fight mostly alone against the Taliban. Abdullah said 11 of his men were killed in their sleep in late January by a Taliban infiltrator posing as a new recruit. Then the Taliban followed up with a coordinated attack on his guard post.

“In this attack, the Taliban hit me hard,” Abdullah said during an interview last month in Kabul. He had come here to get medical treatment for a gunshot wound he received in the attack, and to seek support from Afghanistan’s intelligence agency.

Human rights groups portray Abdullah as being among Afghanistan’s most notorious militia commanders. Human Rights Watch and the human rights division of the United Nations have censured his militia in the past year, citing extrajudicial killings. In an episode in January, one of Abdullah’s sub-commanders killed the 13- or 14-year-old after questioning him about roadside bombs, the boy’s father, Khial Mohammad, said.

“After they killed my son, they said he was involved in planting bombs on roadsides and cooperating with the Taliban fighters,” Mr. Mohammad said. But he added that his son had had no involvement with the Taliban.

Abdullah insisted that he did not kill civilians. The Taliban, he said, not he, were responsible for escalating the brutality.

Abdullah recalled the Americans lecturing him about the laws of war and human rights, but those notions barely seemed to register. He admitted to desecrating the bodies of his enemies.

“Yes, dead bodies are left on the ground,” he said. “We drag their dead bodies with a car.”

The last time he saw the American Special Forces team was some five months ago. “ ‘You did great work with us,’ ” Abdullah recalled the soldiers telling him in parting. “ ‘If we stay in Afghanistan and we need something to get done, we need people like you to do it for us,’ they said.”