KABUL: The US military says it has carried out an airstrike on the northern Afghan city of Kunduz that was captured by the Taliban the previous day.

US Army Col. Brian Tribus, spokesman for the US and NATO missions in Afghanistan, says the airstrike early Tuesday was conducted "in order to eliminate a threat to the force."

The city fell Monday with the Taliban overrunning government buildings and hoisting their flag in the city square.

Sarwar Hussaini, a provincial police spokesman, says Afghan forces have launched an operation on several fronts around Kunduz to try and retake the city.

Kunduz is the first city seized by the Taliban since their regime was overthrown in a US-led invasion in 2001. The city's fall comes as President Ashraf Ghani marks one year office.