A truck filled with natural gas crashed into a wall surrounding a synagogue on the Tunisian resort island of Djerba on Thursday, killing five people and injuring about 20, the nation's official news agency reported.

The TAP agency said the blast appeared accidental. The explosion killed the driver of the truck, a police officer and three others, the agency said.

But Perez Trabelsi, the president of the historic Ghriba synagogue, identified the victims as four German tourists and the truck driver. The German Foreign Ministry had no immediate information.

"I think it's an accident, and that it has no link to the situation in Israel," Trabelsi said, referring to recent attacks on European synagogues stemming from the ongoing violence between Israel and the Palestinians. "If it was an attack, it would have targeted people inside the synagogue." Trabelsi said the synagogue's facade was damaged.

Helicopters brought the injured, who suffered from burns, to Djerba's regional hospital.

Djerba is a popular tourist destination off the southeast coast of the North African nation. Its blue-and-white Ghriba synagogue, set in the middle of an olive grove, is a site of pilgrimage for Jews and is built on the foundations of one of the oldest synagogues in Africa. It was open to visitors at the time of the blast Thursday.

Security services and judicial authorities opened investigations to find the causes of the blast.

As tensions have escalated in the Middle East, synagogues in Europe, particularly in France, have been attacked. In the most serious case, a synagogue in the southern French city of Marseille was burned to the ground March 31.

Tunisia, a predominantly Muslim nation with a population of about 7.5 million, is not known as a hotbed of Islamic terrorism.

"We live with no problems; everything has gone well for us," Trabelsi said.

Tens of thousands of Jews lived in Djerba in the early 20th century, but tensions in the Arab world prompted many to leave. Today, the Jewish community numbers about 2,000.

According to tradition, the first Jews came to Djerba in biblical times, bringing a stone from the ancient temple of Jerusalem that was destroyed by the Babylonians in 586 B.C. The stone is kept in a grotto at Djerba's synagogue.

The first documented evidence of a Jewish community in Djerba dates from the 10th century A.D. By the 18th century Djerba was an important Jewish cultural center and home to traders, craftsmen and Hebrew publishing firms.