Afghan forces battle Taliban in Uruzgan
Afghan forces are fighting back against a Taliban offensive in Tarin Kot, the capital of the strategically important southern province of Uruzgan.
Residents have told the BBC they were forced from their homes by Taliban fighters pushing into the city.
Afghan army reinforcements have arrived and air strikes have targeted militant positions.
Tarin Kot is the latest provincial capital in the sights of the insurgents.
Last month the Taliban closed in on another southern city, Lashkar Gah and in 2015 they briefly captured the capital of Kunduz province in the north.
Sabir Meenawal, a local resident in Tarin Kot, told the BBC that "armed Taliban came to his house at around 10am".
"They asked us to leave. A lot of other families like mine have been forced to leave their houses," he said, adding that fighters used residential buildings to fire on troops.
The governor and police chief of Uruzgan moved to an Afghan military base at the airport, apparently for a security meeting.
There has been fighting at various government compounds, including Tarin Kot prison which is thought to house 400 inmates, many of them suspected Taliban.
'Some police fled'
An Afghan defence ministry spokesman said that reinforcements have arrived in Tarin Kot and that Afghan airstrikes were launched against the militants with Nato assistance.
The reinforcements were reported to include units led by General Abdul Raziq, the prominent police chief of Kandahar.
There have been claims that some government forces abandoned defensive positions around Tarin Kot. Provincial police chief Wais Samim told AFP news agency that some of the city's defences had fallen without a fight.
"Some policemen retreated from their outposts. Some people here deliberately want the enemy to succeed," he told AFP.
The Taliban have been threatening Tarin Kot for months.
Uruzgan is one of the leading poppy cultivating provinces in Afghanistan and is strategically important as it borders the key southern provinces of Helmand and Kandahar.
Over 1,000 Australian troops were stationed in Tarin Kot between 2005 and 2013, before handing security responsibility to Afghan forces.