The Taliban reported taking several key buildings in a siege of Kunduz, a provincial center in northern Afghanistan, after launching a major offensive operation Monday, Reuters said.
The Islamist fighters have captured a 200-bed hospital and several government buildings, Taliban spokesman Zabihullah Mujahid said in a post on Twitter. Earlier, Afghan police said the Taliban attacked Kunduz from three directions.
A police official, who declined to be identified, confirmed to Reuters that a government-run hospital had fallen into insurgent hands.
The Taliban advised Kunduz residents to stay indoors during the hostilities, saying its fighters would do their best not to harm civilians.
Nevertheless, the Pajhwok news agency says at least four residents of the city were killed during the siege and 47 others were injured. Government forces reported four fatalities on their side and said at least 20 Taliban fighters were killed.
Some unconfirmed reports in the Afghan media said the UN ordered evacuation of its employees in Kunduz over the attack and so did several other international organizations.
US-trained Afghan police and army used helicopters to fire rockets at the advancing Taliban forces. Artillery and gunfire could be heard in the city center after dawn.
Kunduz was at the center of fierce fighting between the Taliban and Afghan government forces in April. Taking over the city would be a major victory for the militants, who are seeking to capitalize on the withdrawal of most foreign troops, who handed over most security functions to national forces.
Earlier, Afghan troops drove off the Taliban from most of the ground they took over during the warm weather fighting season.