Sweden summoned Turkey’s ambassador on Monday over concerns that a Swedish citizen, among 11 other activists, risks up to 15 years in prison. Ali Gharavi, an IT consultant and writer, was detained while attending a July 5 workshop in Istanbul along with several other human rights activists. The group included Amnesty International's Turkey director. “We understand that he was in Turkey to participate in a peaceful seminar. We are worried about the accusations against him,” AFP quoted Swedish Foreign Ministry spokeswoman Sofia Karlberg as saying. Turkish prosecutors on Sunday sought prison terms of up to 15 years for the activists, according to Dogan news agency. Gharavi, who is of Iranian origin, has worked as the IT head for international nonprofit group the Center for Victims of Torture.