Iran's Foreign Ministry said Sunday it has no information about an Iranian-American consultant working for George Soros' Open Society Institute who the New York-based organization claims is being detained. Kian Tajbakhsh, an urban planning consultant who has also worked for the World Bank, was detained on or around May 11, according to the Open Society Institute. The group is a private foundation that encourages democracy-building in countries around the world. His detention, and the detention of other Iranian-Americans in Iran, come amid recent accusations by Iranian authorities that the US is using critics and dissidents to try to overthrow the country's hard-line government. "We have no exact report about him from official authorities," said Mohammad Ali Hosseini, spokesman of Iran's Foreign Ministry, when he was asked about Tajbakhsh.