The latest round of rocket attacks against Israeli civilian targets by Palestinian terror groups in the Gaza Strip, who launched several dozen volleys into southern Israel Wednesday, occurred during the visit of Prime Minister David Cameron. Britain has often taken a critical approach to Israel, even under Conservative governments. On this occasion, however, Cameron could only offer support when Israel struck back, hitting 29 targets in Gaza.

What is new in this round of violence is that the rockets are being launched by Palestinian Islamic Jihad, an Iran-backed rival to Hamas. Iran had funded and armed Hamas for several years as well, but had reduced its support after Hamas (reluctantly) abandoned the Assad regime in Syria under pressure from the Sunni world. The fall of the Muslim Brotherhood in Egypt–of which Hamas is the Palestinian branch–was another blow.

Just last week, Israel intercepted a shipment of advanced Syrian missiles from Iran to Palestinian terror groups in Gaza, likely Islamic Jihad. The timing was again fortuitous–Israeli Prime Minister Benjamin Netanyahu was in the United States and was able to demonstrate to the Americans just how little the Iranians cared for peace in the region–but the event itself highlighted strategic shifts that create new challenges for Israel’s fragile security.

As Mitch Ginsburg of the Times of Israel notes, while Israel could choose to respond to the latest rocket fire–for which it holds Hamas responsible, as the governing power in Gaza–by toppling the Hamas regime, that would only help Islamic Jihad. The core problem remains Iran, whose nuclear ambitions and support for terror are not restrained by ongoing international negotiations. Unless that problem is neutralized, the attacks will continue.