Suspected militants have attacked a depot where tankers were being filled with fuel to supply Nato troops in Afghanistan.
As many as 27 transporters were set alight close to the Pakistan capital Islamabad.
Authorities say six people were killed in the raid.
The Pakistan Taliban say they carried out the carnage when 12 gunmen opened fire on guards then set the fire to the trucks.
It is the latest in a series of attacks on overland supply lines running through Pakistan to Afghanistan.
On Friday a number of lorries carrying supplies for NATO forces were set alight in the southern Sindh province.
Pakistan say Nato supply routes through the country will remain closed until public outrage over Nato incursions and drone strikes across the border with Afghanistan stop.