At least 11 people, most of them children, were killed after a series of explosion at an Afghan gas storage facility triggered a fire in a nearby settlement for displaced people, officials said on Tuesday.
It was not immediately clear whether the blasts late Monday on the edge of the relatively peaceful western city of Herat were the result of an accident or caused by a militant attack.
"Around midnight (Monday) a gas tanker exploded which triggered blasts in a gas storage plant, killing 11 people and injuring 10 others," Herat police spokesman Abdul Rauf Ahmadi told AFP.
The explosions triggered a plume of flames into the night sky, which rapidly spread to a nearby settlement of mud houses for internally displaced people where most of the deaths occurred.
Ihasanullah Hayat, spokesman for the governor of Herat, confirmed the toll and said the majority of those killed were children.
A resident of the hillside settlement, who lost a 9-year-old daughter in the fire, said many of the victims were trying to flee the towering flames.
"The explosions were powerful and sparked a huge fire," said the man, who had sought refuge in Herat after fleeing the neighbouring restive province of Badghis.
"After the first explosion everyone started to flee the area and got caught up in the flames," he added, reluctant to give his name.
Mourners gathered at the settlement for funeral prayers on Tuesday morning, with turbaned pall bearers seen carrying bodies for burial on makeshift stretchers.
Domestic gas cylinder explosions are an almost daily occurrence around the country, where safety standards are poor and fatal accidents not uncommon.
Herat province, a key business hub located in western Afghanistan near the border with Iran, is a relatively peaceful province in a country convulsed by an ascendant 14-year Taliban insurgency.
But in May last year four insurgent gunmen launched a pre-dawn attack on India's consulate in Herat before being repelled by security forces, in an assault highlighting the precarious security situation in the country.
And at least four Afghans were killed in September 2013 in a Taliban suicide attack on the US consulate in the city.
The Taliban are stepping up their summer offensive, launched in late April, amid a bitter leadership dispute following the announcement of the death of longtime leader Mullah Omar.
At least 12 people including three US civilian contractors were killed Saturday when a suicide car bomber struck a NATO convoy in Kabul, following a wave of fatal bombings earlier this month that rattled the city.
Mullah Akhtar Mansour, Omar's longtime trusted deputy, was named as the new Taliban chief in late July in an acrimonious power transition.
Al-Qaeda chief Ayman al-Zawahiri recently pledged his group's allegiance to Mansour, in a move which could bolster his accession amid the growing infighting within the Afghan militant movement.
The latest wave of deadly violence underscores Afghanistan's volatile security situation as peace talks appear to have stalled.
Afghan forces, stretched on multiple fronts as the insurgency expands, are facing their first fighting season without the full support of US-led NATO forces.
NATO ended its combat mission in Afghanistan in December last year, although a 13,000-strong residual force remains for training and counter-terrorism operations.