The Taliban have steadily been making gains in surrounding provinces, but in Kandahar, General Raziq’s forces have long been successful in keeping the insurgents at bay. But the general’s control is being tested by this new wave of attacks.

In recent weeks, in addition to firing on security outposts in most of the province’s districts, the Taliban have also carried out heavier assaults and ambushes in at least six districts, often inflicting casualties on Afghan forces.

“For the last two weeks, the Taliban have been attacking the northern districts of Kandahar and have killed many Afghan security forces,” said Noor Nawaz Piawari, a military analyst in Kandahar. “The northern districts are close to Helmand and Uruzgan, which they control in large parts. They are after expanding their territory to create routes that connect to Pakistan,” where most of the insurgency’s leadership is based.

Mr. Piawari said General Raziq would struggle to maintain security as his police forces are stretched and face casualties, with the Taliban often attacking isolated outposts across several districts.

For an Afghan force that lost men in record numbers last year, the past month has proved particularly deadly. The Taliban have overrun three districts across the country in the last week, and the pattern suggests they are focused on inflicting heavy casualties on Afghan forces, rather than holding the territory they take over. When they overrun outposts and police stations, they often capture even more weapons and ammunition, most of it paid for by the United States and its allies to help bolster the Afghan forces.

Both in Janikhel District of Paktia Province, and in Kohistan District of Faryab Province, the Taliban looted all the weapons and equipment left behind by the Afghan forces. In Taiwara District, in western Ghor Province, the Taliban killed as many as 30 government forces.

When Afghan forces took back the district center of Kohistan on Tuesday, they estimated that the Taliban had seized some 40,000 rounds of machine gun ammunition, a mortar with 20 rounds and 30 rocket-propelled grenades, according to Sulaiman Rahmani, a militia commander in the district. The province’s police chief, however, said that whatever the Taliban took had been bombed by the Afghan Air Force.