QUETTA: Pakistan Customs has launched a probe into disappearance of 500 oil tankers and containers carrying supplies for Nato troops in Afghanistan.A senior customs official told media on Sunday that 500 oil tankers and containers which had left Port Qasim in Karachi for Kandahar did not reach the Pak-Afghan border near Chaman.He said that Karachi customs had cleared the vehicles after scanning.The official said the investigation was undertaken after the Supreme Court of Pakistan had taken suo motu notice of reports about the missing vehicles. “We are optimistic that we will trace the missing vehicles and their documents,” he added.Over the past two years more than 60,000 heavy vehicles of Nato have entered Afghanistan via the Chaman border with an average of 100 vehicles a day.Answering a question, the official said that customs officials had verified documents of 174 Nato vehicles at the Customs House in Chaman.Frequent incidents of looting of Nato vehicles were reported last year from Killa Abdullah, Quetta, Kuchlak and other areas of Balochistan – Dawan