KANDAHAR: Taliban forces fought their way deep into the capital of Afghanistan's central province of Uruzgan on Thursday, threatening government offices and capturing a prison before being pushed back, officials said.

The attacks, in one of the country's top opium-producing areas, exposed how thinly stretched Afghan security forces have become as they try to contain Islamist insurgents in other areas of the country.

In Uruzgan, militants had fought to within a few hundred metres of the governor's compound and police headquarters in Tarin Kot, a city of about 70,000 people, but by afternoon, officials said they had repelled the attacks.

Reinforcements included General Abdul Raziq, a border police commander from the southern region of Kandahar with a fearsome reputation, said Dost Mohammed Nayab, a spokesman for the governor of Uruzgan.

Aircraft and helicopters flew over the city, providing air support to embattled government troops, and the Taliban suffered heavy casualties, Nayab added.

The offensive, and apparent government collapse in some areas, were reminiscent of the Taliban's swift but brief capture of Kunduz city last year, the first time the movement had seized a provincial capital since losing power in 2001.

Bolstered by reinforcements and air support, security forces began to push the Taliban back in the early afternoon, said one resident, who asked not to be named for his own safety.

"This morning was very bad, but the security situation is better now," he said. "This morning the circle of fighting was a kilometre or so from the main bazaar. The government and (officials) were all escaping to the airport and trying to get out to Kandahar."

In the aftermath of the fighting, streets remained deserted and shops closed, with many families fleeing the city, the resident added.

"The city won't be back to normal for a month at least. The shops, bakeries, restaurants are all closed. There are no vehicles on the streets, the city is just shut down."

Blame game begins

Leaders in Uruzgan had retreated to the airport, home to an Afghan military base, said a police official, who asked not to be named as he was not authorized to speak to the media.

In the Afghan capital, Kabul, a spokesman for President Ashraf Ghani expressed confidence in the security forces in Tarin Kot.

"Uruzgan will not turn into a terrorists' safe heaven," said Shah Hussain Murtazawi.

In telephone interviews with Reuters, security officials were quick to assign blame for the initial collapse of the defences.

Provincial police chief Wais Samim said many officers in the city had made deals with the Taliban and abandoned checkpoints without a fight, while another police official accused the province's senior leadership of abandoning the city.

In a statement late on Wednesday, the Taliban promised government forces protection if they surrendered peacefully.

The city's prison fell to the advancing militants, but its occupants had previously been transferred to the airport, said Abdul Karim, head of the Uruzgan provincial council.

In an online statement released early in the day, the Taliban said their fighters had entered the city and overrun at least seven checkpoints as well as the prison, with officials taking the prisoners as "hostages" and fleeing to the airport.

Taliban militants have been waging an insurgency against the Western-backed government for 15 years, since they were toppled by a US-led military intervention in 2001.

Last year, the government retook Kunduz only after nearly two weeks of fighting, with elite Afghan troops backed up by US special forces and warplanes.

A spokesman for the US military command in Kabul said officials were monitoring the situation, but there were no coalition advisers in Uruzgan and no US air strikes during the latest fighting this week.

At least 69 coalition troops died in Uruzgan during nearly a decade and a half of international military efforts to defeat the Taliban and other militant groups after 2001.

The province is in a part of south-central Afghanistan long dominated by the Taliban and warlords who vie for access to its lucrative smuggling routes and illicit drug production.

Uruzgan's opium output jumped 22 percent last year, the United Nations said.