Two survivors of last week's gas truck explosion at an ancient synagogue believe it was a deliberate attack that killed 16 people, including three Germans who died Sunday.

Germany's Bild am Sonntag newspaper on Sunday quoted a witness as saying the tanker truck already was outside the Ghriba synagogue on this resort island when he and other tourists arrived. Tunisian authorities have said the tanker truck bumped into a synagogue wall while turning around and then exploded in a "tragic accident."

"That can't be. It was there all the time," Helmut Eckart, a 59-year-old engineer from Berlin, told the newspaper.

He said the truck was parked "right in front of the entrance" to the synagogue.

"It struck me as odd: a man got out, closed the doors. Then, he went away quickly toward the town," Eckart said. "He was maybe in his early 30s and was wearing blue overalls with spots of paint. That must have been the attacker."

Eckart, who was vacationing with his wife, said he had time to leave his tour bus and reach the back of the synagogue before the explosion.

Another tourist, Siegfried Mueller of Hamburg, told the newspaper, "It was definitely an attack."

A day earlier, German Interior Minister Otto Schily told German television, "We now believe it was an attack."

Tunisian authorities, who say the blast was a "tragic accident," are investigating.

"At this stage of the investigation, nothing justifies anything beyond the preliminary conclusions which showed that this was an accidental explosion," said a Tunisian official close to the government, speaking on condition he not be identified further.

The explosion came amid a spate of anti-Semitic attacks in Europe that have coincided with growing violence in the Middle East.

On Saturday, about 50 youths attacked the central synagogue in Kiev, Ukraine, beating three people with stones, hurling bottles and breaking about 20 windows, the rabbi said.

Kiev's chief rabbi, Moshe-Reuven Azman, said Sunday the mob marched down the Ukrainian capital's main boulevard shouting "Kill the Jews!" before attacking the synagogue.

In Rome, anti-Jewish slogans were painted on walls and a pro-Palestinian march was held in which some participants dressed up as suicide bombers.

Meanwhile, three more Germans died Sunday in German hospitals from their injuries in the blast in Tunisia, raising the death toll to 16. Altogether, the explosion killed 11 Germans, three Tunisians — the driver of the truck and two workers — a French man and a French-Tunisian tour guide.

The three Germans who died Sunday in German hospitals included two women and a severely burned 18-month-old infant, said Mario Kueppers, a spokesman for tour operator TUI. At least four Germans remain in critical condition.

The 2,000-year-old synagogue, the oldest in Africa, was flush with tourists at the time of the blast. Djerba, about 375 miles south of Tunis, is the symbolic hub of the Muslim North African nation's approximately 2,000-strong Jewish community.

Tourism Minister Mondher Zenaidi said "there should be no speculation" about an attack on the Ghriba synagogue until the investigation is completed.

The only recollection of an anti-Jewish attack in Djerba was the Oct. 8, 1985, killing of three people in the business district by a Tunisian policeman. He was apparently seeking revenge for the Israeli raid a week earlier on PLO headquarters, then housed outside Tunis.