Some 40 road tankers supplying fuel to American troops in Afghanistan have been destroyed by suspected pro-Taleban militants on the border with Pakistan.
The attacks, at the Pakistani border crossing point of Torkham, wounded about 70 people who had gathered in a nearby field.
Foreign forces in Afghanistan receive much of their fuel through Pakistan.
Elsewhere, seven Afghans working on mine clearance projects have been killed in incidents in the north.
Five of the de-miners were killed on Sunday in Jowzjan province, which the BBC's Alastair Leithead in Kabul says is normally peaceful. Two more employees were killed on Monday in Kunduz province.
The attack on the fuel tankers took place at about 2000 local time on Sunday.
Local officials said two explosions were heard in an area where more than 100 fuel lorries had been parked for the night, waiting to cross the border and deliver fuel to US forces in Afghanistan.
As drivers tried to evacuate the area and escape the flames one truck carrying oil exploded and crowds were showered with burning oil.
Local officials said more than 70 had been injured and were taken to hospitals on both sides of the border.
Locals said 50 shops were also destroyed.
Our correspondent says there have been a number of incidents like this in the past few weeks, all thought to have been sabotage and blamed on insurgents as they were attacking vehicles connected with international forces in Afghanistan.
'Hundreds of bullets'
In the incident in Jowzjan province, a group of mine clearance workers were attacked by four men on two motorbikes in the district of Fayzabad while on their way back to their base camp in the district of Oqacah.
Five de-miners were killed and seven others travelling in the truck which was attacked were badly injured.
Farib Elmi, the Deputy Director of the Afghan Technical Consultants group, who they worked for, said hundreds of bullets were fired from AK47's and heavy machine guns in the ambush which lasted some minutes.
"The area is safe according to our information and there have been no incidents like this before. This is the first case we have seen," Mr Elmi said.
He said he did not know who might have been responsible.
This part of Afghanistan is thought to be an area where the Taleban have little influence.
Farid Homayoun of the Halo Trust, the biggest de-mining group in Afghanistan, condemned the attack and appealed to all parties to respect de-miners who he said were "very neutral across political and ethnic groups".
"Killing innocent de-miners is not going to achieve anything and is working against the quarter of the population that are affected by land mines," Mr Homayoun said.
On Monday, gunmen in Kunduz province opened fire on a car carrying employees of Mine Detection and Dog Centre, the NGO said.
One of the de-miners and the driver were killed.
A Taleban spokesman (Zabihollah Mojahed) condemned the killings: he said the Taleban never attacked mine clearance workers.