CHAMAN: Authorities said Friday they had seized a cache of arms and ammunition being smuggled into the country from Afghanistan after an exchange of fire on the southwestern border.The unknown smugglers left their vehicle loaded with weaponry after exchanging fire with Pakistani forces deployed at Chaman, a town bordering Afghanistan's Kandahar province, late Thursday, an official of the paramilitary force said. The official, who declined to be identified, said the action was taken following an intelligence tip-off that arms and ammunition were being smuggled into Balochistan for sabotage activities. The cache included six RPG rocket launchers and an anti-tank mine as well as mortar bombs, hand grenades and a machine gun. Pakistani officials have claimed that arms are being smuggled from Afghanistan to support a tribal insurgency.