WASHINGTON - The US military is rapidly expanding its Central Asian supply routes to the war in Afghanistan, fearing that Pakistan could cut off the main means of providing American and NATO forces with fuel, food and equipment, The Washington Post reported. Experts said US officials prompt news media reports such as this one every time tensions erupt in the US-Pakistan relations. On Sunday, the Post recalled that Pakistans temporary closure of a major crossing into Afghanistan in September, resulting in a logjam of hundreds of supply trucks and fuel tankers, dozens of which were destroyed in attacks by insurgents. While reducing the shipment of cargo through Pakistan would address a strategic weakness that US military officials have long considered an Achilles heel, shifting supply lines elsewhere would substantially increase the cost of the war and make the United States more dependent on authoritarian countries in Central Asia, the newspaper said. A senior US defence official said the military wants to keep using Pakistan, which offers the most direct and the cheapest routes to Afghanistan. But the Pentagon also wants the ability to bypass the country if necessary. With landlocked Afghanistan lacking seaports, and hostile Iran blocking access from the west, it said Pentagon logisticians have limited alternatives. Its either Central Asia or Pakistan those are the two choices. Wed like to have both, the defence official said, Wed like to have a balance between them, and not be dependent on either one, but always have the possibility of switching. US military officials said they have emergency backup plans in case the Pakistan routes became unavailable. We will be on time, all the time, said Vice Admiral Mark Harnitchek, deputy commander of the US Transportation Command, which oversees the movement of supplies and equipment. In such an event, however, the military would have to deliver the bulk of its cargo by air, a method that might not be sustainable; it costs up to 10 times as much as shipping via Pakistan, the Post said. Wed have to be a little bit more mindful of what we put in the pipe, Harnitchek said. Citing unnamed Pentagon officials, the Post said that in 2009, the United States moved 90 per cent of its military surface cargo through the Karachi port and then through mountain passes into Afghanistan. Now almost 40 per cent of surface cargo arrives in Afghanistan from the north, along a patchwork of Central Asian rail and road routes that the Pentagon calls the Northern Distribution Network, the newspaper said. The military is pushing to raise the northern networks share to as much as 75 per cent by the end of this year, the paper said. In addition, the US government is negotiating expanded agreements with Kazakhstan, Uzbekistan and other countries that would allow for delivery of additional supplies to the Afghan war zone, The Post said. The United States also wants permission to withdraw vehicles and other equipment from Afghanistan as the US military prepares to pull out one-third of its forces by September 2012, the paper noted. US President Barack Obama announced last month that 10,000 troops would leave this year and all 33,000 personnel sent as part of a surge ordered in late 2009 would be home by next summer, leaving a US force of some 65,000. There are currently up to 150,000 foreign troops in Afghanistan, including about 99,000 from the United States. Obama has indicated a series of drawdowns until Afghan forces assume security responsibility in 2014. Meanwhile, the United States drew a blank when it approached China a couple of years ago to open a major supply route on its soil to U.S. forces in Afghanistan, a leading American newspaper reported Sunday, citing diplomatic cables unveiled by anti-secrecy website WikiLeaks. The Washington Post, which carried the story, said China rebuffed the idea as military relations with Washington soured. According to a February 2009 cable, the US State Department had directed its Embassy in Beijing to make a formal proposal to Chinas Foreign Ministry to permit the overland transit of supplies to US and NATO troops, the newspaper report said. The supply route would have followed railroads in China before crossing into Kazakhstan, Uzbekistan and Tajikistan, said the February 10, 2009 document, signed by Secretary of State Hillary Clinton. The move by Washington to seek help from China was aimed at reducing its dependence on Pakistan. The cable noted that China had expressed interest in cooperating with the US for delivery of non-lethal aid to Afghanistan as far back as 2006. It also said the Pentagon was seeking only to move non-lethal items such as food, tents, blankets and construction material through China. Private commercial carriers would have been used, and no US military personnel would have been present along the route. The cable noted that a new Chinese route would provide an efficient and effective alternative to increasingly unstable Pakistani land routes, and could potentially costless, than new supply lines crossing from Europe to Central Asia. A cable sent in response three days later by the US Embassy in Beijing reported that Chinas Ministry of Foreign Affairs had agreed to consider the idea but was noncommittal. Deng Hongbo, deputy director of the ministrys Department of North American and Oceanian Affairs, welcomed the proposal and promised the Chinese side would study the idea and respond as soon as possible, the cable stated. China kept mum about the overture for months. Then in June 2009, a Chinese official raised Washingtons hopes during a meeting with a US diplomat in Kazakhstan, according to the report. The Chinese official dined with Richard Hoagland, then the US ambassador to Kazakhstan, at a revolving restaurant on the top of a high-rise hotel in Astana, the capital. The official, who preferred to meet in public places because he believed his own embassy was thoroughly bugged, said the Chinese government was actively researching the US supply route proposal, according to a US cable. The official confided, however, that Chinas Foreign Ministry and Defence Ministry were divided on the subject and said it would be hard for some officials to swallow the idea of giving active support to a NATO military operation, the report said. My own personal opinion, the official told Hoagland, is that we will do the right thing and cooperate with NATO and the US government. But the Pentagons hopes for cooperation were dashed several months later. China suspended military relations with the United States in January 2010 to protest the sale of $6 billion in weapons to Taiwan.