The Taliban launched a coordinated attack on the Afghan city of Kunduz on Sunday night, reportedly infiltrating the city's defensive line and attacking from four different directions.
Brigadier General Charles Cleveland, spokesman for Afghanistan's NATO-led forces in Kabul, told Reuters he had not seen evidence of a major attack by the Taliban, although he was aware of reports of sporadic fighting in Kunduz.
Reuters also reported at least five Taliban fighters with AK-47s and rocket propelled grenades were seen entering the city, and that fighters were entrenched inside residential buildings.
According to the BBC, residents reported hearing heavy fighting and helicopters flying over the city.
Afghanistan's interior ministry announced that reinforcements were being sent to the area.
The city on Kunduz was briefly captured by the Taliban last September in what was then seen as one of the biggest blows to the western-backed government in Kabul since the withdrawal of international troops in 2014.
The fresh attack comes a day before a major donor conference in Brussels, where Afghanistan's international partners are expected to approve maintaining billions of dollars in funding for the government over the next four years.