Kunduz, Afghanistan: Taliban insurgents advancing on the capital of a northern Afghan province have captured a key adjoining district, officials said on Sunday, sparking renewed alarm among residents who fear the fall of the besieged city.

The Taliban launched their annual spring offensive in late April with a brazen assault in Kunduz province, coming close to overrunning the provincial capital and sending civilian casualties soaring in outlying districts.

Afghan forces prepare for battle with Taliban on the outskirts of Kunduz. Credit:Reuters

The capture of Chardarah district - on the edge of Kunduz city - on Saturday reignited concerns over its potential fall.

"The district has fallen to Taliban after hours of fierce fighting" Chardarah district chief Mohammad Yousuf Ayubi said. "Twelve Afghan forces have lost their lives and 17 have been wounded."