A 30-year old woman blew herself up in the center of the Tunisian capital Tunis on Monday, wounding nine people including eight police in what the Interior Ministry called a “terrorist explosion”.

Witnesses described a blast on the central Habib Bourguiba avenue where hundreds of police later cordoned off an area near the capital’s landmark Municipal Theatre and the French embassy.

“I was in front of the theater and heard a huge explosion,” witness Mohamed Ekbal bin Rajib told Reuters.

Ambulances could be heard rushing to the scene.

Shops were shut on the avenue, usually one of the busiest streets in the capital and site of protests that toppled long-serving leader Zine El-Abidine Ben Ali at the start of the 2011 “Arab Spring” of regional revolts.

The bomber had no previously known militant background, state news agency TAP said, citing the interior ministry.

Tunisia, which is heavily dependent on tourism, has improved security since a series of militant attacks targeting tourists caused the near collapse of the sector three years ago.