Story highlights

The Torkham Gate border crossing is a major transit point for NATO supplies

The Taliban claim responsibility for the assault by suicide attackers

Three militants and one member of the Afghan security forces are killed in the violence

The United States ships about 33,000 tons of cargo out of Afghanistan each month

CNN  — 

Militants attacked a transit point for NATO supplies on the Afghan-Pakistani border early Wednesday, prompting a firefight that left at least four people dead and damaged more than a dozen vehicles, a government official said.

The Taliban claimed responsibility for the assault on the Torkham Gate border crossing area, calling it a complex operation by several suicide attackers on contractor trucks used to ferry supplies for the NATO-led International Security Assistance Force.

CNN was first alerted to incident by Twitter.

Ahmad Zia Abdulzai, a spokesman for the governor of eastern Nangarhar province, said Afghan security forces fought a group of armed suicide bombers for more than two hours. The firefight left one member of the Afghan Public Protection Forces dead and at least five other people wounded, he said.

The bodies of three suicide attackers were also found after the fighting, Abdulzai said.

There were no ISAF casualties, said Lt. Col. Latondra Kinley, a spokeswoman.

The border crossing area has been hit several times before and remains an attractive target for militants.

On average, the United States ships about 33,000 tons of cargo out of Afghanistan each month.

The attacks come as the United States is trying to get Afghanistan to sign an agreement to keep some U.S. troops in the country after 2014.

But the majority of the gear for the 47,000 troops still in Afghanistan will have to be brought out as American involvement in the war winds down.

CNN’s Aliza Kassim and Masoud Popalzai contributed to this report.