Israel refuses to rule out Gaza ground operation following rocket attacks As each side blamed the other for starting the violence, Ehud Barak, the Israeli defence minister, disclosed that Israeli air strikes had killed 15 Palestinian militants in the territory in the past week. The group has largely avoided launching rockets since Israel launched a major ground assault in Gaza in December, 2008 that killed more than 1,000 militants and civilians. The operation led to a large reduction in rocket fire, although sporadic attacks were mounted by smaller militant groups in Gaza. Until Wednesday, Hamas fighters are only believed to have fired rockets on two occasions. Mr Barak delivered a stern warning that Israel could be forced to take more robust action if the rockets continue. "If we have no choice and the fire will continue, then they clearly will be hit harder and nothing is out of the question," he said. If we need a ground operation, there will be a ground operation. Despite the gravity of the situation, analysts said they believed both sides would work through unofficial channels to resolve the stand-off. Previous flare ups in recent years have been resolved through Egyptian mediation. The violence will come as an embarrassment to the Emir of Qatar, who became the first foreign leader to hold talks with Hamas officials in Gaza when he visited the territory on Tuesday. Qatar, an important Western ally, has hosted the Hamas leadership in exile since it left Damascus last year in protest at and was seen as a potential moderating influence over the movement.