Israel said on Friday it would not bow to international pressure to end air strikes in Gaza that officials there said had killed almost 100 Palestinians, despite an offer by U.S. President Barack Obama to help negotiate a ceasefire with militants.
Asked if Israel might move from the mostly aerial attacks of the past four days into a ground war in Gaza to stop militant rocket fire, Prime Minister Benjamin Netanyahu replied, "we are weighing all possibilities and preparing for all possibilities."
"No international pressure will prevent us from acting with all power," he told reporters in Tel Aviv a day after a telephone conversation with Obama about the worst flare-up in Israeli-Palestinian violence in almost two years.
On Friday Washington affirmed Israel's right to defend itself in a statement from the Pentagon. But Defence Secretary Chuck Hagel told Israeli Defence Minister Moshe Ya'alon he was concerned "about the risk of further escalation and emphasized the need for all sides to do everything they can to protect civilian lives and restore calm."
A rocket caused the first serious Israeli casualty - one of eight people hurt when a fuel tanker was hit at a service station in Ashdod, 30 km north of Gaza, and Palestinian militants warned international airlines they would fire rockets at Tel Aviv's main airport.
Medical officials in Gaza said at least 75 civilians, including 23 children, were among at least 99 people killed in the aerial bombardments which Israel began on Tuesday. They included 12 killed on Friday.
Israel's military commander, Lieutenant-General Benny Gantz, said his forces were ready to act as needed - an indication of a readiness to send in tanks and other ground troops, as Israel last did for two weeks in early 2009.
"We are in the midst of an assault and we are prepared to expand it as much as is required, with whatever force, and for as long as will be required," Gantz told reporters.