In April 2010, Washington stepped up its efforts to impose a new round of sanctions on Iran over its nuclear program. Key powers such as Turkey, India and China opposed the adoption of a new round of sanctions against Tehran. As a result, the US Congress has delayed arms sales sought by the Turkish military. However, questions have been subsequently raised over the continued presence of US nuclear weapons being reportedly stationed at the air base during the Cold War as part of the NATO nuclear sharing program, after recent parliamentary debates in Belgium and Germany called for the removal of weapons stationed there under the same program. Bilkent University Professor Mustafa Kibaroğlu speculates that if the Obama administration presses for the withdrawal of these weapons, which Turkey wishes to maintain, then Turkey-U.S. relations may be strained.