First NATO trucks move into Afghanistan from Pakistan after 7-month closure Because Afghanistan is landlocked, supplies have to be trucked in from Pakistan Pakistan reopens routes after Clinton apologizes for "friendly fire" incident that killed 24 Transporters who resume supplies will be "considered a friend of the U.S.," the Taliban say (CNN) -- Trucks carrying supplies to NATO troops crossed from Pakistan into Afghanistan for the first time in seven months on Thursday after Islamabad agreed to reopen routes, officials said. The four trucks, under heavy security, crossed the border from Chaman in Pakistan's Balochistan province. Because Afghanistan is landlocked, many supplies for NATO-led troops fighting Islamic militants there have to be trucked in from Pakistan. On Tuesday, Islamabad decided to reopen the crucial supply routes shut down on November 27, a day after coalition forces mistakenly killed 24 Pakistani troops. The incident plunged U.S.-Pakistan relations to an all-time low. The Pakistani routes offer a shorter and more direct route than the one NATO has been using since November that went through Russia and other nations, avoiding Pakistan altogether. The talks to reopen routes had been stuck on two key issues -- Pakistan's demand to charge more per container shipped across its border, and Pakistan's demand the United States apologize for the friendly fire incident in November 2011. On Tuesday, U.S. Secretary of State Hillary Clinton apologized. Costs for the Pakistani route ranges somewhere around $250 per truck. Pakistan had been seeking $5,000 per truck as a condition of reopening the supply lines, something the United States said it would not pay. The U.S. military will now pay Pakistan $1.1 billion it owes as part of the deal struck to reopen the NATO supply lines, according to U.S. officials who had knowledge of the agreement's details but weren't authorized to speak publicly. Meanwhile, the Pakistani Taliban has threatened to attack NATO trucks, saying the supplies are used to target its members fighting against occupation in Afghanistan. Transporters who resume supplies will be "considered a friend of the U.S." and will face the consequences, a spokesman for the militant group said Wednesday. Journalist Ayza Omar contributed to this report.