US Secretary of State Hillary Clinton on Saturday defended her plans to meet Uzbek leader Islam Karimov, saying US contacts with the authoritarian regime can help improve the ex-Soviet country's rights record. Clinton is visiting the impoverished ex-Soviet nation of Tajikistan and will later fly to neighbouring Uzbekistan to meet Karimov who has wielded unchecked power in his Central Asian state for 22 years. Karimov's bloody crackdown on a rare burst of unrest in the city of Andijan in 2005 left 187 people dead, according to official figures, or many hundreds, according to rights groups. US ties with Uzbekistan have for years been a delicate balancing act as Washington seeks to encourage its government to improve its rights record while trying to secure Tashkent's support in its war on terror, given its strategic border with war-ravaged Afghanistan and its existing railway infrastructure. "If you have no contact you will have no influence, and other countries will fill that vacuum who do not care about human rights," Clinton said in Tajikistan, referring to her plans to meet the Uzbek leader. "It's a balancing act, but we try on an ongoing basis to get our message across and give heart to people inside countries that there are those outside who care about what is happening to them and are advocating for change on their behalf." "I cannot promise you that there will be some immediate change...you know that change in many of these situations takes time and effort," she said at a town-hall style meeting with Tajik youth and civil society in the capital Dushanbe. She was speaking in response to a woman who asked why she was meeting with an authoritarian leader like Karimov. Ahead of Clinton's meeting with the Uzbek leader Human Rights Watch called on the top US diplomat to press Uzbekistan to release political prisoners, end torture in jails and promote civil society. "The visit to Tashkent is the first since the administration’s controversial move in September to lift longstanding restrictions on financial assistance, including military assistance, to Uzbekistan," the advocacy group said, noting the restrictions were put in place in 2004. A senior State Department official, speaking to travelling reporters on condition of anonymity, said the Uzbek government was making progress on human rights. "I'd say we do have - we do see more willingness on the part of the Uzbeks to work with us on a lot of these big concerns that we have, like trafficking in persons, like religious freedom," the official said. Moscow, which regards both Tajikistan and Uzbekistan among its close allies, is expected to keep a watchful eye over Clinton's trip. Mindful of accusations of human rights violations at home, Russia has traditionally steered clear of criticising Karimov, at least publicly. Tashkent hosted a US airbase near the Afghan border after the September 11 terror attacks in the United States, but closed it down in 2005 after the US government criticised Karimov's 2005 crackdown. Clinton's stop in Tajikistan and a visit to Uzbekistan later in the day extend a tour that previously took her to Kabul and Islamabad as Washington grapples for an exit to the US-led 10-year military conflict in Afghanistan. She is on a mission to promote her new Silk Road project linking the economies of Tajikistan and Uzbekistan with those of Afghanistan, Pakistan and other central Asian countries, part of a long-term plan to boost regional peace and stability. It is her first visit to Tajikistan, which shares a porous 1,340-kilometre (830-mile) border with Afghanistan, and her second trip to Tashkent since one in December 2010.