At least 18 people have been killed after attackers opened fire at a petrol station in south-western Pakistan, triggering a huge blaze, officials say.

Reported victims of the attack in the Balochistan town of Khuzdar included seven women and four children who had been sitting in a van at the station.

No group has so far claimed responsibility for the attack.

Balochistan is seen as a Taliban and al-Qaeda stronghold. Separatists are also active in the province.

Anti-insurgent groups, believed to be raised and supported by security forces, also operate in the area.

Charred bodies

The Khuzdar attack happened late on Friday afternoon, senior Khuzdar official Abdul Mansoor Kakar told reporters.

He said the gunmen attacked a passenger van, and one of the bullets hit petrol pumps as the vehicle was refuelling.

This triggered a massive fire, leaving some bodies charred beyond recognition.

Balochistan is one of Pakistan's most impoverished provinces, despite having vast natural resources.

It has also been plagued by sectarian violence in recent months - with many attacks by hardline Sunni Muslims on the minority Shia community.

On top of all that, says the BBC's Ilyas Khan in Islamabad, Balochistan is now facing an acute administrative crisis and power struggle amid the uncertainty of national elections next spring.

Last month, the Balochistan government was told in a Supreme Court ruling that it had "lost the authority to govern the province", adds our correspondent.