Gunmen in south-western Pakistan have attacked and set fire to nearly 30 tankers carrying fuel to Nato troops in Afghanistan, officials say.
The gunmen torched the convoy parked near a roadside restaurant near the town of Sibi in a pre-dawn raid.
The Pakistani Taliban have carried out a series of similar attacks since last week, when the authorities closed the main border crossing to Afghanistan.
Islamabad's move was in protest at an earlier incursion by Nato helicopters.
The Nato and US have since apologised for last week's raid, which killed at least two Pakistani soldiers.
Nato admitted two of its helicopters entered Pakistan on 30 September and killed two border guards, mistaking them for militants after they fired shots.
Pakistan says three soldiers were killed.
The attack infuriated public opinion in Pakistan and led to anti-Nato demonstrations.
About 20 gunmen attacked the tanker convoy on Saturday, local Pakistani official Neem Sherwani told Reuters.
"The attackers first fired shots and then fired small rockets at the tankers. Twenty-eight to 29 tankers caught fire," the official said.
The tankers were on their way to the town of Chaman, on the border with Afghanistan, reports say.
The Pakistani authorities closed the Torkham crossing in the north-west after the Nato incursion. The move has stalled hundreds of lorries carrying Nato supplies bound for Afghanistan, making them easy targets for militants.
The Chaman crossing in Balochistan remains open, but this is not as convenient for supplies bound for Kabul.
No group has so far claimed responsibility for the latest raid.
The Pakistani Taliban have said they carried out earlier attacks on tanker convoys.