in Afghanistan without an apology. Pakistan decided to reopen the supply lines after US Secretary of State apologized on July 3, 2012, for the Salala incident. An agreement was signed on 31 July 2012 between U.S. and Pakistani officials which allowed NATO supply convoys to cross into Afghanistan from Pakistan up to the end of 2015, one year beyond the deadline for withdrawal of U.S. combat forces. Northern Distribution Network Afghanistan also borders Turkmenistan, Uzbekistan, and Tajikistan, so alternate supply routes, termed the Northern Distribution Network, existed to move supplies into Afghanistan through these countries. However, these routes were longer and costlier than the routes through Pakistan. Routes There were several different routes included in the Northern Distribution Network. The most commonly used route, though also one of the longest, started at the port of Riga, Latvia on the Baltic Sea, and continued for 3,212 miles (5,169 km) by train southwards through Russia, using railroads built by Russia in the 1980s for the Soviet–Afghan War. The supplies then passed through Kazakhstan and Uzbekistan before reaching Afghanistan's northern border at Termez. To get to the south of the country, the supplies had to be loaded onto trucks and transported through the mountainous Hindu Kush by means of the Salang Tunnel. The Salang Tunnel, which is the main connection between northern and southern Afghanistan, is 1.5 miles long and situated at an altitude of 11,100 feet. The route is prone to avalanches and quite dangerous. Another, more southern route started at Poti, Georgia on the Black Sea and continued to Baku, Azerbaijan where the goods were transferred to barges and ferried across the Caspian Sea. Supplies landed in Turkmenistan and then moved by rail through Uzbekistan before arriving at the Afghan border. In 2010, this route carried one third of the NDN's traffic. Over one-third of all of the nonlethal equipment including fuel, clothing, and food used by the U.S. Department of Defense in Afghanistan traveled through Baku at one point. A third route, created in order to avoid going through the often volatile country of Uzbekistan, went from Kazakhstan to Kyrgyzstan and then through Tajikistan before reaching Termez. History The Northern Distribution Network was established in 2009 in response to the increased risk of sending supplies through Pakistan. Initial permission for the U.S. military to move troop supplies through the region was given on January 20, 2009, after a visit to