As the fighting between Israel and Hamas goes from escalation to conflagration, the first reports of missiles fired at major Israeli cities may foreshadow a larger war.

First, the Israeli Defense Forces are now confirming that rockets have been fired by Hamas (and other terrorist groups in Gaza) at Tel Aviv and Jerusalem, the two largest Israeli cities, fulfilling a threat the terrorist organization made yesterday if Israel continued its strikes against Hamas targets in Gaza. 

Hamas also claimed to have fired a rocket at Haifa, Israel's third-largest city near the border with Lebanon, but there hasn't been confirmation yet.

Since Hamas took over Gaza in 2007 following the Israeli disengagement two years earlier, the cycle of violence has followed a particular regimen: Hamas haphazardly lobs a few rockets at small Israeli towns in the south and Israel responds with targeted airstrikes. International calls for restraint are issued and the sides return to their tense standstill until the next violent episode ensues.

Until this week, there have been two major exceptions: The Gaza Wars of 2008-2009 and 2012 (also known as Operations Cast Lead and Pillar of Defense). In those battles, the rivulet of missile fire expanded into a stream, bringing bigger Israeli cities under fire and increasing the death toll, particularly on the Palestinian side as Israeli forces strike targets in densely populated Gaza. 

This newest battle has quickly evolved into a heightened kind of confrontation. Like the 2012 war, there was a major instigating factor. Last time, it was Israel's assassination of Ahmed Jabari, the leader of Hamas' military wing in Gaza; this time it's the upshot of tensions following the kidnapping and murder of both three Israeli teenagers and one Palestinian teenager in a suspected revenge attack.

The question now is whether this war will go the way of the first Gaza War, which ultimately led to a ground invasion by Israel and placed it at the center of an international firestorm. Israel's cabinet, echoing Prime Minister Benjamin Netanyahu's threats, has authorized a call-up of reservists for a possible ground invasion. If Israeli cities remain under fire, it seems entirely likely that the invasion will go forward and this will snowball into another major crisis.

While rumors of a possible ceasefire are swatted away as soon as they circulate, Israeli Defense Minister Moshe Ya’alon, said this about the call-up:

I don’t know how many of that number we will have to draft but the intention here is to field a force that knows how to properly deal with the Gaza Strip.”

In the meantime, the death toll among Palestinians has crept into the double digits and Israelis in most major cities remain within range of bomb shelters as the air raid sirens continue.