Afghanistan is a "very productive area" for engagement between the United States and its arch foe Iran, a US official declared Friday, at a meeting in Moscow aimed at curbing rising violence in the conflict-torn country. The meeting, led by the Shanghai Group which groups China, Russia and Central Asian states, came amid mounting international concerns over the resurgence of the Taliban Islamist militants in the country. "We see Iran as an important player related to Afghanistan. We see this as a very productive area for engagement in the future," the US official, who asked not to be named, said on the sidelines of the conference.