Taliban tighten grip on Afghan city of Kunduz

Taliban fighters have seized a military hilltop site in Kunduz, tightening their grip on the northern Afghan city.

The capture of the Bala Hisar fortress came despite efforts by government reinforcements, backed by Nato airstrikes and special forces, to retake the city.

It leaves the airport as the army's last stronghold.

The Taliban overran Kunduz on Monday, their biggest military gain since they lost power in 2001.

The Taliban had blockaded the Bala Hisar fortress for two days. Hundreds of Afghan security personnel were stationed there, and their fate was not clear.

Late on Tuesday the Taliban tried to capture the airport as well, but two US air strikes halted their advance.

Clashes went on through the night around Kunduz, and the provincial hospital was reportedly struggling to cope with the number of casualties.

Kunduz is one of Afghanistan's largest cities, and is strategically important as a transport hub for the north of the country.

Militant violence has increased across Afghanistan since Nato ended its combat mission in Afghanistan in December, leaving a 13,000-strong residual force used for training and counter-terrorism operations.