What is driving the current Israel-Gaza violence?

Smoke rises following Israeli air strikes on a building in Gaza City (Hatem Moussa/AP)

Israel and Palestinian militants in the Gaza Strip have exchanged fire in the worst bout of cross-border violence since an 11-day war between Israel and Hamas last year.

Israel has carried out several deadly air strikes, among them the targeted killing of a senior commander from the Palestinian Islamic Jihad, an Iran-backed militant group.