Jerusalem - Israel was placing its police forces on high alert Wednesday for the Passover festival which begins at sundown.

Thousands of police, Border Police and Civil Guard volunteers are to guard synagogues, holy places and hiking sites. The Magen David Adom, Israel's equivalent of the Red Cross, also stepped up its state of alert and reinforced its stations with ambulances and medical teams.

Police officials were quoted as saying that militant organizations had high motivation to carry out attacks during the festival. On Tuesday night, Israel's counter-terrorism bureau issued a warning cautioning Israelis against travelling to the Sinai peninsula for the holiday.

The bureau said it had information that several militant groups were planning to attack Israelis in the peninsula, a popular travel destination during Israeli holidays.

A Palestinian suicide bomber killed 30 people in 2002 when he blew himself up in a hotel in the coastal city of Netanya as guests were sitting down to begin the ritual meal which ushers in Passover.

The seven-day Passover festival (eight days outside of Israel) commemorates the Biblical Exodus from Egypt.

Jews traditionally usher in the holiday with a special festive meal, reading from the Haggadah, a collection of texts recounting the Exodus and laying out the ritual for the meal.

The meal itself includes special food with a symbolic significance, such as a vegetable, usually parsley, dipped into salt water to symbolize tears shed as a result of the Jews' slavery in Biblical Egypt, bitter herbs to symbolize the bitterness of slavery, and a special paste made of fruit and nuts, the colour and texture of which is to remind Jews of the mortar the ancient Israelis used to bond bricks when they were slaves in Egypt.

Jews are also forbidden from eating bread products during the entire festival, and have to make do with matzo, unleavened flat bread which does not rise during baking.

On Wednesday morning, 50,000 people participated in a special "blessing of the sun" prayer at Jerusalem's Western Wall, and thousands more elsewhere in the country also observed the ceremony.

The ritual takes place only once every 28 years when, according to Jewish tradition, the sun reaches the exact spot it stood in the heavens at the moment it was created.(dpa)