(Source : voanews) The United States has apologized to Pakistan for last week's helicopter raid that killed Pakistani soldiers near the Afghan border. Despite the apology, the key border crossing for NATO's overland supply lines border remains closed and Taliban militants have destroyed more than 100 trucks in the past week. Thousands of other trucks now sit idle, waiting for the main crossing to reopen. Gunmen stormed a truck depot on Nowshera district late Wednesday, burning some 26 vehicles. Earlier, another group of vehicles was attacked near the southern city Quetta. NATO supply routes have long been targeted by Pakistani militants, but the cluster of attacks following the Torkham border closure has highlighted the vulnerability of the route. Truck drivers at the Torkham crossing on Wednesday said they had been left stranded by the closure, with many forced to stay with their NATO supply containers to try to protect them from theft or attack. Driver Haider Khan Afradi said drivers are now at risk throughout their journey. "We are always in danger when we start from Karachi towards Torkham up to Kabul. There is no security for us and we are suffering a lot," Khan told the Associated Press.