New York Times: An Israeli military official said three infantry brigades were “preparing for a worst-case scenario,” confirming that a ground invasion of Gaza could follow the bombardment from the air.

Hostilities between Israel and the Palestinians worsened with mob violence between Jews and Arabs in Israeli cities while rockets and missiles streaked overhead.

Israel claimed the assassinations of senior Hamas militants and pounded both military and residential areas across Gaza. The militants have fired more than 1,000 rockets aimed at cities across central and southern Israel. Above, a building in central Gaza was leveled to the ground after an Israeli air raid today.

An Israeli military official said three infantry brigades were “preparing for a worst-case scenario,” confirming that a ground invasion of Gaza could follow the bombardment from the air.

But the most shocking developments occurred on the streets of Israel, as rival Jewish and Arab mobs attacked cars, shops and people in several cities, leaving some fearing that the decades-old Israel-Palestinian conflict was heading into new territory.

More than 50 Palestinians including at least 14 children have been killed, according to Gaza health authorities, and in Israel the death toll reached at least seven people including a 6-year-old. A U.S. envoy is heading to the region to urge calm. Airlines in the U.S. have started to cancel flights to Israel.