Gunmen attacked a truck stop just outside of the Pakistani capital Wednesday, killing seven people and torching a convoy of tankers and trucks bound for NATO forces in Afghanistan.

Pakistani officials say 10 to 15 gunmen began shooting at the depot, just 10 kilometers from Islamabad, early Wednesday before setting about 60 containers on fire. They say the attackers then fled in cars and on motorcycles. Officials say some of the casualties were truck drivers.

One driver says he was sitting inside his truck when the attack began and heard the gunmen saying "kill the drivers" and not to let anyone escape.

Militants have attacked trucks carrying supplies for U.S. and NATO forces in the past, but this is the first attack to take place so close to Islamabad.

Officials are investigating and surveying the damage as the charred trucks sit jumbled together at the depot.

Some information for this report was provided by AP and AFP.