Tunis, May 10 : At least four people were shot dead by a guard at the El Ghriba synagogue on the Tunisian island of Djerba, the Interior Ministry said on Wednesday. The 2,500-year-old synagogue is the oldest in Africa and the attack on Tuesday night took place during an annual pilgrimage to the island, which attracts Jewish visitors from Europe and Israel. In a statement, the Ministry said the accused killed a colleague and seized his ammunition before heading toward the synagogue. He opened fire at security units stationed near the synagogue, leaving two visitors and another security officer killed, before being shot dead during an exchange of fire. At least five security officers and other four civilians were injured and rushed to hospital for treatment. "The synagogue and its possessions were cordoned off and all those inside and outside were secured," said the Ministry, adding that an investigation was underway to determine the motive behind the "treacherous and cowardly" attack. Local media reported earlier that an exchange of fire near the Ghriba synagogue was heard. The Ghriba synagogue has fallen victim to several terror attacks in the past. In 2002, a suicide bombing at the synagogue killed 21 people and a soldier shot dead five people, including four Jews, in 1985. The annual pilgrimage to Djerba, about 500 km from the capital Tunis, has had tight security since the bombing. Tunisia is a majority-Muslim country, but Djerba is home to hundreds of Jews. /IANS