Palestinian fighters from the Israeli-blockaded territory claimed responsibility for what Israel described as an unusual attempted attack.

Most attacks from Gaza in the past few years have been by rocket shootings at Israeli towns.

The Islamic Jihad group said it had floated the explosives out to sea in a joint operation with two other groups including the al-Aqsa Martyrs Brigades, the armed wing of the Fatah faction led by Mahmoud Abbas, the Palestinian president.