Tunisia says it has heightened security for the Jewish pilgrimage to the age-old Ghriba synagogue after the Bardo museum attack in Tunis that left 22 people dead, mostly foreign tourists.

Tour operators estimate that around 500 foreign visitors, including people from France, Israel, Italy, Britain and the U.S., will participate in the pilgrimage to Africa's oldest synagogue on Djerba island Wednesday and Thursday.

Police and military presence has been increased and roadblocks have been installed at all entrances to the city and around hotels.

Tour operator Rene Trabelsi says predicted tourist numbers are lower than normal, as some are expected to have changed their minds after the March 18 attack on the National Bardo Museum that was claimed by al-Qaida.