Fierce fighting is continuing between Afghan forces and the Taliban in parts of Afghanistan's northern city of Kunduz, despite government claims that it had regained control of the city.

On Thursday afternoon Taliban fighters seized back the main square and raised their flag there once again.

However eyewitnesses say most of the city now appears to be under government control, despite resistance.

Kunduz was the first major centre to fall to the Taliban in 14 years.

Street battles took place all day on Thursday as government forces pushed back the insurgents who seized the city on Monday.

Many Taliban fighters have now retreated to the outskirts of Kunduz.

The Taliban has denied the city has been retaken.

The city's capture on Monday by the militant group was a huge blow to President Ashraf Ghani, coming on the first anniversary of his taking power.

Praising the work of Afghan forces on Thursday, the president said he hoped that they had "proved to the people of Afghanistan, to the region and to the world that they have the ability and resolve to fight".

A doctor at the hospital in Kunduz told the BBC that they were struggling to cope with the high number of injured people coming in.

A businessman living near Traffic Square in the city centre described the situation as "very, very tense" and said the fighting was still going on as darkness fell on Thursday evening.

Kunduz, with a population of around 300,000, is one of Afghanistan's largest cities and strategically important both as a transport hub and a bread-basket for the region.

The government assault - backed by Nato special forces and US air support - began overnight on Thursday, with fighters infiltrating the city and launching a series of simultaneous attacks from different positions.

Government officials said on Thursday morning that the military had taken back key offices and as many as 200 Taliban fighters had been killed in the operation. Some residents spoke of seeing dead bodies of Taliban fighters everywhere.

Interior ministry spokesman Sediq Sediqqi said an operation to "clear the city" of the last pockets of resistance was ongoing and could take some days.

There were scenes of jubilation at dawn on Thursday as residents emerged from their homes to thank government troops after three days of crippling food shortages.

But the mood changed during the morning as fighting broke out again.

Taliban fighters had scattered into groups of 10 and 12 and were firing at government troops "from inside people's houses and from the top of high-rise buildings," said Samad Ahmadi, a university lecturer, taking shelter on the outskirts of the city.

A doctor with Medecins sans Frontieres (MSF) in Kunduz, Heman Nagarathnam, told the BBC that 296 people wounded in the fighting had been treated at the MSF trauma centre since Monday. Sixty-eight of those treated were children, he said.

The Taliban launched its assault on Kunduz from multiple directions on Monday night, helped by infiltrators who had entered the city during the recent Eid festival. The assault was swift and took Afghan forces by surprise.

The city's capture is a setback for a government under pressure to show it can keep the country secure without the backing of international forces.

Jawed Ludin, the former deputy foreign minister of Afghanistan, told the BBC's Today programme that Kunduz was known to be at risk from terror attacks and the government should have done "a better job" at protecting the city.

Afghanistan's chief executive officer Abdullah Abdullah admitted the government must address its "shortcomings" over Kunduz.

Militant violence has increased across Afghanistan since Nato ended its combat mission there in December 2014, leaving a residual force used for training and counter-terrorism operations. Most of that force is made up of US troops and there are fears Washington plans to pull most of them out in the coming year.