Scores of Israeli tanks have already been deployed near the Gaza border for a possible ground invasion.
Dozens of military trucks were seen transporting tanks and armored personnel carriers toward Gaza late on Thursday. Many buses carrying soldiers also headed toward the border area.
Senior cabinet minister Moshe Yaalon confirmed on Friday that Israel was considering a ground operation against the Palestinian enclave.
At least 25 Palestinians, including a senior Hamas commander, have been killed and over 250 others injured in Israeli attacks in Gaza since Wednesday when the Israeli army launched the so-called "Operation Pillar of Defense" against the Palestinian territory.
Five people, including a woman, were killed in Israeli airstrikes on Gaza City and Khan Yunis on Friday. Many others were also injured in the attacks.
The Israeli Army says it has carried out 466 air strikes against Gaza in the past three days. Palestinian fighters have also fired hundreds of rockets into Israel in response to the deadly attacks. Palestinian rockets have hit several Israeli cities, including Tel Aviv. It is the first time that Tel Aviv has come under attack in decades.
Israeli media reports say the Iron Dome missile shield has only intercepted one-fifth of the rockets fired from the Gaza Strip since Wednesday.
Meanwhile, a Palestinian rocket landed near the US Embassy in Tel Aviv, witnesses said.