NATO says, its war effort in Afghanistan has not been impeded by a row with Pakistan that has left its supply routes vulnerable. Attacks on convoys have soared since Pakistan shut a key border-crossing because of a NATO air-strike which killed at least two soldiers. Talking to media, a spokesman for the NATO – led International Security Assistance Force, Brigadier-General Josef Blotz, said their operations were not impeded at all by these incidents and only a third of it's fuel supplies came via Pakistan. He said the publication of a joint inquiry into last week's NATO helicopter attack could help bring about the reopening of the border route through the Khyber Pass. An initial investigation found the helicopters attacked a border post after Pakistani guards fired warning shots and that the incident could have been avoided with better communication. An estimated 6,500 oil tankers and other supply vehicles are waiting for the crossing to reopen, including around 150 tankers stranded at the Torkham crossing.In the latest attacks blamed on militants, at least 40 tankers carrying fuel for NATO were destroyed on Wednesday.