The fourth attack in six days on NATO oil tankers killed one person and burned at least 20 vehicles.
The attack outside the city of Quetta was claimed by Tehrik-i-Taliban Pakistan, which said the assaults "will further intensify attacks with the intensification of US drone strikes" in the country.
Beyond the "Taliban", however, the political and military story is the Pakistani Government's acceptance of the attacks on its American ally. Islamabad is still blocking the key supply route to Afghanistan through the Khyber Pass. While another route into southern Afghanistan is still open, the Khyber Pass road has been the main supply line. About 70% of NATO's supplies in Afghanistan come through the Pakistani port of Karachi.
Dan Murphy of the Christian Science Monitor summarises, "The danger lies in what the border closing says about the Pakistani military's ability to call the political shots two years after the restoration of civilian rule, their ongoing ambivalence about the NATO effort in Afghanistan, and Pakistan's complicated interests in Afghanistan."
There is no reference in the article to any danger lying in the sharp increase in US drone attacks or in raids by American forces from Afghanistan, even though Islamabad shut down the Khyber Pass route after three Pakistani soldiers were killed by US helicopters flying across the border.
More as the situation develops....