Unknown armed men in southwestern Pakistan Sunday torched two oil tankers, carrying oil for the NATO forces in the neighboring Afghanistan, police in the region said.

Police said that Afghanistan-bound two oil tankers were coming from the port city of Karachi when armed men riding a motorbike set ablaze the two tankers in Bolan district of Balochistan province.

No one was hurt in the attack. The gunmen fled after the attack. Police and fire brigade personnel reached the site and extinguished the fire.

No group claimed responsibility for the attack. But suspected militants routinely target NATO supplies trucks and oil tankers mostly in Pakistan's northwest and attacks in Balochistan are rare.

Officials say that about 70 percent supplies for up to 160,000 U.S.-led NATO troops are transported through Pakistan.

The United States has signed deal with Russia for alternate supply route in view of frequent attacks on NATO trucks in Pakistan.