The international agreement on Iran's nuclear program moves forward Monday with the first meeting of the Joint Commission responsible for monitoring how both sides implement their parts of the deal. Monday's session brings high-ranking officials from Iran and the group that includes the United States, Britain, China, France, Russia, Germany and the European Union back to Vienna, the city where they agreed in July to limit Iran's nuclear program in exchange for needed sanctions relief. It follows Sunday's so-called Adoption Day when the sides took their first formal steps to implement the deal. The commission is due to meet four times a year to discuss issues such as the design for converting the heavy water research reactor in Arak, projects at the Fordow facility, and any issues that arise from implementing the lifting of sanctions. "I welcome this important step forward, and we, together with our partners, must now focus on the critical work of fully implementing this comprehensive resolution that addresses our concerns over Iran's nuclear program," Obama said.