Three tankers were destroyed while 12 were damaged.
The attackers opened fire on the tankers late Sunday at an industrial site in Pakistan's capital, Islamabad. Another seven people were injured in the attack, Mohammad Nazir, a police investigator, said.
"Four to five people arrived on the scene and opened fire at the tankers and the crew," Nazir said. "Following the attack, the attackers managed to flee before the police arrived on the scene."
Mohsin Bhati, an official at the District Headquarters Hospital in Rawalpindi, the garrison town that adjoins Islamabad, said that rescue workers took three burnt bodies there. "Of the seven injured, three people have burn injuries and four bullet wounds."
The attack followed the destruction by insurgents Friday of another convoy of 27 fuel tankers for NATO troops in landlocked Afghanistan, who receive 80 percent of their supplies overland via Pakistan. The Taliban claimed responsibility for the raid.
The Pakistani government Thursday shut down one of the most heavily used supply routes for NATO convoys in retaliation for the increasing number of attacks by Afghanistan-based NATO units on targets in the border region with Pakistan that serve as a base for militant groups in Afghanistan.
The action was taken in response to a NATO helicopter attack on a Pakistani border post in which three troops died and three more were injured.
NATO said the helicopter fired rockets in self-defence after it came under fire from the ground. Pakistan has demanded an apology for the incident and compensation.
The US has intensified drone attacks against Taliban and Al Qaeda fighters launching cross border attacks on international forces in Afghanistan.
In September, the US Central Intelligence Agency (CIA) carried out at least 21 drone strikes on suspected Taliban strongholds in the mountains of Pakistan, the highest of any month, The New York Times reported. The next highest monthly total was 11 strikes in January.
At least 123 alleged militants, including some foreign fighters linked to Al Qaeda, have been killed in the CIA attacks.