Rockets have landed both deeper into Israel, striking cities like Ashkelon and Beersheba, and with greater intensity than at any time since Israel's devastating military offensive against Gaza in December 2008 that killed 1,400 people.
The result has been to sow panic, with Israeli schools within rocket range being ordered to close until the weekend, and take the territory to the brink of a new war.
Since the end of Operation Cast Lead, as Israel code-named its 2008 incursion, Hamas has largely refrained from firing rockets into Israel, but is accused of allowing smaller groups to mount attacks, albeit on a much smaller scale than in years past.
But in a sudden departure from what Israel calls "the rules of the game", Hamas fired 50 mortar shells at Israeli military positions this week and unusually claimed credit for the attacks.
The sudden change of tactic comes against the backdrop of protests, violently put down in Gaza, that have seen 100,000 people take to the streets of Palestinian towns to demand an end to the Islamist's group long-standing rift with Fatah, its moderate, secular rival that controls the West Bank.
Scared of being engulfed by the popular protests sweeping the region, Hamas is trying to divert its people's wrath to a common enemy: Israel.
But its rivals, the Palestinian Islamic Jihad, whose armed wing is known as al-Quds Brigades, have upped the ante by striking Israeli cities with Graduate rockets, two of which were fired at Beersheba yesterday. Seeking to capitalise on Palestinian outrage after nine people, three of them children playing football, were killed in an Israeli retaliatory strike on Gaza, the group vowed to escalate its attacks yesterday
"From now on, there are no more red lines for the resistance as long as the enemy keeps killing civilians," a spokesman said.
But it is far from clear that either want a fully-fledged war and yesterday Hamas, clearly alarmed by Israeli threats, promised to "restore calm" in Gaza. With anger mounting in Israel, such attempts to defuse tension may well have come to late.