In his letter addressed to his Azerbaijani counterpart Ilham Aliyev, U.S. President Barack Obama thanked the Azerbaijani leader for support to peacekeeping mission in Afghanistan, expressing hope that bilateral ties will be deepening.

“The United States recognizes Azerbaijan’s important contributions to regional and international security. It is my hope that we will be able to broaden and deepen our relationship in the months and years ahead,” reads the letter, the Trend News reports, referring to the text published by Reuters.

In the letter handed by U.S. Secertary of Defense Robert Gates, Obama appreciates Azerbaijan’s efforts in the Karabakh peace process under mediation of U.S., Russia and France and warns the country 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,” Obama said.

He also expressed gratitude to Azerbaijan for sending troops to Afghanistan and opening its air space for transit of U.S. and NATO forces.

“Azerbaijan’s leadership in the development for a Southern Corridor for energy has also increased regional prosperity and enhanced global energy security,” U.S. President stated.