Israeli troops are massing on the Gaza border, preparing for a possible strike. A major incursion is planned if the Palestinian authorities do not return an Israeli soldier abducted during an attack by militants on a border post at the weekend.Two troops were killed in the raid, carried out by fighters from the armed wing of the ruling Hamas party and other factions. Israel has hinted it might now target Hamas leaders as well as government-owned infrastructure in Gaza. A deadline has been given to Palestinians to release Corporal Gilad Shalit, a 19-year-old conscript tank gunner who holds Israeli and French citizenship. It is believed he may have been wounded in Sunday’s attack. He is the first soldier to have been seized in such an operation since 1994. Several gunmen lobbed grenades at his tank after emerging from a 300-metre tunnel dug under the Gaza border fence at the Kerem Shalom crossing. Israel says it holds both Prime Minister Ismail Haniyeh and President Mahmoud Abbas ultimately responsible. Both men have called for the soldier to be well treated if he is being held. Abbas says efforts are being made to find him.