Israel has given a Gaza-bound Libyan aid ship an ultimatum of midnight tonight to change course. An organiser of the mission on board, Mashallah Zwei said Israeli authorities have contacted them by radio to give them until midnight tonight to change course and head to the Egyptian port of El-Arish. He said Israel has otherwise threatened to intercept the boat with their navy. Mr Zwei, a member of the Kadhafi Foundation charity which organised the shipment, told AFP by satellite phone the Israelis were told the request would be studied before a response is given. He said he explained to the Israeli authorities that their original destination was Gaza and that they are not for a provocation. In Israel, a military spokeswoman said it has begun preparations to prevent the ship from reaching the Gaza Strip in defiance of a naval blockade on the Palestinian territory. According to the Kadhafi Foundation, the 92-metre freighter, Amalthea, left a Greek port on Saturday and was expected to arrive off Gaza's territorial waters tomorrow.