Heavy fighting is under way in parts of the northern city of Kunduz between Taliban fighters and Afghan forces, as the Taliban retook some areas they lost overnight, our correspondent says.
"Fighting is going on since early morning and Taliban have claimed they have gained some parts of the city they had lost last night," Al Jazeera's Qais Azimy, reporting from Puli Khumri, about 100km from Kunduz, said on Thursday.
"They [Taliban] said they had left the centre of the city because of heavy bombardment by Nato forces and now they are trying to get it back. Many of them have taken shelter in residential areas around the city," he said.
"The fighting seems to have spread to neighbouring province of Takhar and Baghlan. We are getting reports of Taliban taking control of a district in Baghlan province," Azimy said.
Government troops backed by NATO forces and US air strikes had taken control of parts of Kunduz on Wednesday three days after the Taliban captured the northern city.
At least 50 people, mostly civilians, have been killed and more than 300 others injured in the battle, sources told Al Jazeera.
"The Afghan government is putting pressure on security forces to regain areas they lost but it is a big challenge as Taliban have claimed to have established their government. They have appointed a governor and police chief.
"One Taliban commander from the area told me that they are ready to fight and not planning to leave the area."
Afghan government officials however, still insist they are in control of the area.
"It is retaken and being cleared from terrorists, with heavy casualties to the enemy," Interior Ministry Spokesman Sediq Sediqqi said on Twitter.
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"Civilians are got caught in the fight and paying a heavy price. Hospital sources in the area say they keep receiving injured and dead bodies but they can't identify if they are civilians or Taliban fighters," our correspondent said.
"They are facing big shortage of medicine and staff as many doctors have left the area due to the fighting."
The Taliban attack on Kunduz began at dawn on Monday with the fighters capturing key buildings and freeing hundreds of prisoners, who included members of the group.
The ensuing fighting between the Taliban and security forces sent thousands of residents fleeing.
The incursion came after two failed attempts this year to capture Kunduz city, which has been encircled by the fighters for about a year.
The takeover was the group's biggest victory since the Taliban government was ousted in 2001.
"The fact that the Taliban can actually take the sixth largest city in Afghanistan, and hold it for a couple of days, sends a signal to the government and the international community about the future of Afghanistan," said David Sedney, a former deputy US Assistant Secretary of Defense for Afghanistan and Pakistan.
He told Al Jazeera that to improve the country's security, the government must take several measures, including getting the military organised.
"The Afghan government doesn't even have a defence minister after one year of unity government. This is a government that needs to get down to business and not just talk about having a better security situation.
"Afghan soldiers are great fighters ... They're willing and able to fight but they need a good leadership."
President Ashraf Ghani took office a year ago pledging to restore peace to Afghanistan.
The US and NATO troops play a vital role in training and assisting the Afghan forces. US air strikes on Tuesday and Wednesday hit Taliban positions during fierce fighting for control of Kunduz's airport.
Source: Al Jazeera and agencies