The Taliban have taken the strategically important city of Ghazni, the 10th provincial capital to fall to the militants in less than a week.
Afghan security forces arrested Ghazni’s governor and his deputy after they fled the city.
Ghazni is on the major Kabul-Kandahar motorway, linking militant strongholds in the south to the capital, Kabul.
Taking Ghazni is thought to increase the likelihood that the Taliban could eventually aim to take Kabul itself.
Almost a third of the country’s 34 provincial capitals are now under Taliban control.
The insurgents have moved at speed, seizing new territories almost daily, as US and other foreign troops withdraw after 20 years of military operations.