Russia extended its military presence in Tajikistan for 30 years on Friday in a deal to secure the southern fringes of its former Soviet empire after NATO troops leave Afghanistan. The countries\' defence ministers signed an agreement prolonging Russia\'s lease on a base in the former Soviet republic until 2042 during a visit by President Vladimir Putin, Reuters reported. The lease had previously been due to expire on Jan. 1, 2014, the same year most foreign combat troops are due to leave Afghanistan, which shares a long, mountainous and porous border with Tajikistan. More than 6,000 soldiers stationed across three towns in Tajikistan comprise Russia\'s Base 201, the Kremlin\'s biggest troop deployment abroad and a bulwark against any spillover of Islamist militancy into its post-Soviet hinterland. Addressing soldiers and officers at the base, Putin aired familiar complaints about NATO, saying Russia was concerned about expansion of infrastructure of the alliance, which now includes several former Soviet satellites. \'I believe (NATO) is to a large degree a throwback of the Cold War,\' Putin said. But he suggested the alliance could be a positive force as long as it does not try to usurp the power of the U.N. Security Council, where Russia has veto power. \'To some degree, under certain circumstances, if it acts on a mandate of U.N. Security Council, NATO can play a positive role,\' Putin said. \'We will develop our relationship with this organisation.\' Putin has been a harsh critic of NATO operations from the bombing of Serbia in 1999 to the air strikes that helped oust Libyan leader Muammar Gaddafi in 2011, and has cast the United States as a meddler out to stamp its will on the world.