Hamas attack shocks Israel, but what comes next?

Fifty years on from the Yom Kippur War, which began with a surprise attack on Israel by Egypt and Syria, Palestinian militants have launched a major assault.

This too was unexpected, on another Jewish holiday.

Tensions had recently risen in the Gaza Strip, but the conventional wisdom was that neither Hamas, the Islamist group which governs there, nor Israel wanted an escalation.

Instead, Hamas had been planning a sophisticated, coordinated operation.

Early on Saturday morning, as an intense barrage of rockets was launched with some reaching as far away as Jerusalem and Tel Aviv, Palestinian fighters entered southern Israel by sea, land and air.

They have held Israeli towns and army posts under siege for hours, killed many people and taken away an unknown number of Israeli civilians and soldiers to hold as hostages in Gaza.