Germany's Interior Minister says the April 11 truck explosion at a historic Tunisian synagogue was definitely a terrorist attack.

Interior Minister Otto Schily says Germany is "100 percent" convinced the truck explosion at the El Ghriba synagogue was the work of terrorists. The blast, on the Tunisian resort island of Djerba, killed 16 people, including 11 German tourists.

The Tunisian government initially called the incident "a tragic accident," but is continuing to investigate.

The German Interior Minister made his comments Monday following a two-day visit to Tunisia where he met with investigators and Tunisian President Zine al Abidine Ben Ali.

Mr. Schily said he is convinced it was a terrorist attack because of the way gas tanks were mounted on the truck, the substances in the tanks and how the explosion took place.

An estimated one million Germans visit Tunisia each year. But Mr. Schily said he did not feel it is necessary to issue a travel warning to German citizens as a result of the fatal truck explosion.