Pakistani fire fighters try to extinguish the burning NATO oil tanker following an attack in Rawalpindi near Islamabad, Pakistan, Oct. 4, 2010. At least 12 people were killed as 28 NATO oil tankers were attacked by unknown militants early Monday morning in Rawalpindi, according to local media. [Xinhua]

At least 12 people were killed as 28 NATO oil tankers were attacked by unknown militants early Monday morning in Rawalpindi, a city near Pakistan's capital Islamabad, reported local media.

According to the report, nine unknown militants riding on motorcycles opened fire at a NATO convoy nearby the DHA Phase II area of Rawalpindi, a city which is only about half-an-hour ride south of Islamabad. The attackers also pulled out of the people from the trucks and shot them dead, said eyewitnesses.

Monday morning's attack on NATO supply trucks is the third of its kind and also the most serious of its kind over the past three days following the air strikes by NATO helicopters in Pakistan's territory on Thursday, which killed three Pakistani troops and injured three others.

Early on Friday morning, some 20 militants attacked a NATO convoy with rockets in Shikarpur, a city in the northern part of Pakistan's Sindh province, killing three people and having 27 NATO oil tankers completely burnt.

Later on Friday evening, another two NATO supply trucks were attacked by a rocket in the country's southwest city of Khuzdar, during which two people were killed.