US Defense Secretary Robert Gates handed Obama’s letter to President of Azerbaijan Ilham Aliyev during his Sunday visit to Azerbaijan. Since 2001, tens of thousands of military aircraft and supply trucks have crossed the country carrying U.S. and NATO forces and equipment to Afghanistan. The Pentagon wants to avoid problems that could slow Obama’s 30,000-troop surge. "The United States recognizes Azerbaijan’s important contributions to regional and international security," wrote in the letter published by the Reuters Agency. "It is my hope that we will be able to broaden and deepen our relationship in the months and years ahead," Obama wrote. "I am aware of the fact that there are serious issues in our relationship, but I am confident that we can address them," Obama’s letter said. Obama praised Azerbaijan’s commitment to efforts to resolve the Nagorno-Karabakh conflict, mediated by the United States, Russia and France, and warned against using force. "I believe that a peaceful resolution to the Nagorno-Karabakh conflict is essential for the long-term stability of the South Caucasus region, and support for this outcome will remain a priority for the United States. “At present the USA does not even hide its interest in the relations with Azerbaijan. It also demonstrates its interest in strategic partnership with Baku not only in the oil sphere but also in the context of geopolitical cooperation, as Azerbaijan is located not far from Iraq and Afghanistan", he said. "It is my hope that we will be able to broaden and deepen our relationship in the months and years ahead." In the letter, Obama praised Azerbaijan for sending military personnel to serve in Afghanistan and opening its land and air space to help re-supply U.S. and NATO forces there.