Iran's judiciary said Ms Ebadi's group did not have the required legal permits
Iranian police have raided and closed the office of a human rights group led by the Nobel laureate, Shirin Ebadi.
Judiciary officials said the centre was acting as an illegal political party, and had contacts with local and foreign organisations, local media reported.
The raid came shortly before the centre was to host a celebration for the 60th anniversary of Human Rights Day.
Ms Ebadi, who has repeatedly criticised Iran's human rights record, said it would not stop her supporters' work.
"We will meet again somewhere else and will continue to support the rights of activists and political prisoners," she told the Associated Press.
In a statement, the judiciary said it had ordered the closure of the Human Rights Defenders Centre in Tehran because it did not have the required legal permits, the Mehr news agency reported.
It had also been "promoting illegal activities such as issuing statements on different occasions, sending letters to domestic and foreign organisations, holding press conferences, meetings and conferences" which created an atmosphere "of media publicity against the establishment in recent years", the statement added.
Ms Ebadi became the first Muslim woman to win the Nobel Peace Prize in 2003 for work that included promoting the rights of women and children in Iran and worldwide.