BERLIN, April 22 -- A natural-gas truck explosion that killed 17 people at a historic synagogue in Tunisia 11 days ago was a deliberate attack, the Tunisian and German governments said today.
Tunisian officials initially said the explosion, in which 11 German tourists were killed, appeared to be an accident. But in a statement today, the government called the blast the work of a Tunisian named Nizar Nawar and a relative living in the country.
The announcements came at the end of a two-day visit to the North African country by German Interior Minister Otto Schily, who even before his visit expressed skepticism about the accident theory.
"Germany is now convinced that this was 100 percent a criminal, terrorist act," Schily said at a news conference.
In recent days, the investigation in Tunisia has uncovered a phone call to Germany by the alleged bomber just before the blast, and indirect and still tentative links between alleged accomplices and the Hamburg terror cell that led the Sept. 11 attacks on the World Trade Center and the Pentagon.
German investigators say they increasingly believe the explosion was the work of al Qaeda, the terrorist network of Osama bin Laden. Nothing so far is conclusive and Schily said today that "for the time being, we can't say it was al Qaeda."
If confirmed as an al Qaeda attack, it would be the first completed by the group outside Central Asia since Sept. 11. An effort to detonate explosives aboard a Miami-bound American Airlines jet in December was foiled by passengers; investigators say that the Briton subdued on the plane, Richard C. Reid, was an al Qaeda operative.
Schily said there is "technical proof" that the truck that blew up in a narrow passageway at the entrance to the Ghriba synagogue on the resort island of Djerba was deliberately detonated.
Before the blast, the German Embassy in Tunisia had received a letter from a group called "al Qaeda Tunis," warning that German goods "will be burned and poisoned" if Germany "does not uncouple itself from the club of colonialism" and end its relationship with the "Zionist entity," a common term in the Arab world for Israel.
After the attack, a group directly linked in the past to al Qaeda, the Islamic Army for the Liberation of Holy Sites, asserted responsibility. Authorities are taking the claim seriously because a faxed statement by the group to two London-based Arabic newspapers contained the name of the truck driver before authorities had released it.
According to German media reports, Nawar, 25, who had lived in Lyon, in southern France, called a contact in Germany immediately before the blast. During the call, which was intercepted by German intelligence, the driver, when asked if he needed anything, replied, "I only need the command."
German officials say Nawar placed his call to Christian Ganczarski, 35, a Polish-born German citizen who had converted to Islam. He was well known as an activist in radical Muslim circles in the western German city of Duisburg, according to reports here. Police detained and questioned Ganczarski before releasing him without charge.
Ganczarski had previously lived in Afghanistan, German officials said.
Ganczarski told officials that he met Nawar in August 2001 in Pakistan, the news reports say. By this account, the two became friendly and exchanged telephone numbers, but Ganczarski denied any involvement with al Qaeda.
Ganczarski also was an acquaintance of Mouhamedou Ould Slahi, who was extradited to the United States by the government of Mauritania on suspicion of involvement in the millennium plot to bomb the Los Angeles airport, according to the reports.
The two are said to have attended the same mosque in Duisburg.
Slahi lived in Germany from the mid-1990s to September 1999 and during that period visited bin Laden-sponsored camps in Afghanistan at least twice, according to a reporter at a German television network who communicated with Slahi by e-mail.
During a search of Ganczarski's apartment, police reportedly also found the bank account number of the wife of a man who had witnessed the last will and testament of Mohamed Atta, the leader of the Hamburg cell.
German police also searched other apartments after the Tunisian attack and briefly detained a number of men. One of those held, a Moroccan identified as Karim M., had the phone number of Ramzi Binalshibh, a member of the Hamburg cell who is now wanted on an international arrest warrant.