The deadly air strike that hit a hospital in the Afghan provincial capital of Kunduz was a mistake, the US commander of international forces in Afghanistan said.
US Army General John Campbell said in a testimony on Tuesday to the Senate Armed Services Committee that the decision to carry out the strike was made within the US chain of command.
"To be clear, the decision to provide aerial fires was a US decision made within the US chain of command," Campbell said in testimony on Tuesday to the committee.
"A hospital was mistakenly struck. We would never intentionally target a protected medical facility."
Meanwhile, fighting erupted in the embattled city of Kunduz after the Taliban attacked a police headquarters overnight, and officials warned that food and other emergency aid could not get through to the city.
The clashes and the dire warnings on Tuesday underscored the weak hold authorities have on Kunduz, a strategic city whose brief fall to the Taliban last week was an embarrassing blow to President Ashraf Ghani.
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Al Jazeera's Qais Azimy, reporting from Kunduz, said gunfire and artillery could be heard almost every second in the city.
"Strong fighting is going on and it has not stopped. Afghan security forces are struggling to get control of the city - they are fighting the Taliban on almost every single street in Kunduz.
"I talked to an Afghan security official here in Kunduz, and he told us that the reason they are going so slow is because they are facing a lack of leadership and coordination. Also that the Taliban are hiding in residential areas, and it is hard to go after them because they [Afghan forces] are trying to avoid civilian casualties," Azimy said.
The Afghan government has also been criticised for ignoring warnings earlier of Taliban threats to the city.
Battles have raged around Kunduz for the last nine days as government forces, backed by US air strikes, have tried to drive out Taliban fighters.
The Taliban managed to overrun and hold Kunduz for three days last week until government forces launched a counter-offensive on Thursday. Its brief capture was one of the Talibans' biggest victories.
Overnight to Tuesday, several Taliban fighters managed to re-enter the city centre and attack Kunduz police headquarters and other government buildings, said Sarwar Hussaini, the spokesman for the provincial police chief.
By Tuesday morning, some gunmen had pushed their way close to the main city square. "Fighting is also going on with the Taliban near the Ghazanfar Bank, close to the main square," Hussaini said.
Kunduz residents reported hit-and-run attacks by the Taliban, with the group making incursions into the city centre from far-flung rural areas, engaging troops, then retreating again.
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Aslim Sayas, a deputy head of the Afghan disaster management, said it was still too dangerous and unpredictable for supplies to be trucked into Kunduz. Instead, he said authorities were helping the population that has fled from Kunduz.
"Right now we are providing food and non-food items to refugees and displaced people in Takhar, Badakhshan and Balkh," he said, referring to northern provinces to the east and west of Kunduz.
US air strike on hospital
Moreover, a bombing early on Saturday of a hospital in Kunduz belonging to Doctors Without Borders (MSF) - in which at least 22 people were killed - has raised wider questions as to the circumstances that led to the prominent medical charity being hit in an apparent US air strike.
Medicines, too, have not been delivered to hospitals, and the air strike on the MSF trauma centre had closed an essential medical facility in the war-torn city.
The Ministry of Public Health issued a statement calling for "a thorough, impartial investigation by an independent inquiry team" into the Saturday bombing of the hospital.
Circumstances remain unclear, and the Afghan government and US military have launched investigations into the incident.
The ministry said the attack had jeopardised "vital health, medical and surgical work of international and local health personnel" working in Afghanistan.
"Staff no longer feel safe in any health facility anywhere in the country. And some international health organisations are questioning whether the risks of staying in the country are just too high after such an attack," it said.
Source: Al Jazeera and agencies