JERUSALEM -- Israel's military said Wednesday that Palestinian militants in the Gaza Strip fired four rockets at southern Israel.

Two were intercepted by the Iron Dome missile defence system, it said, and there were no reports of injuries or damage.

Hours later, Israeli airstrikes targeted several Hamas military sites in the northern Gaza Strip. No injuries were reported.

The rocket attacks from the Palestinian enclave were the first in nearly a month and came amid quiet, international efforts to bolster an informal truce between Israel and Gaza's ruling Hamas militant group.

There was no immediate claim of responsibility for the rocket fire.

In November, Israel and the militant group Palestinian Islamic Jihad fought the worst round of violence in months after the Israeli military killed a senior Islamic Jihad commander.

Israel and Hamas have fought three wars and dozens of smaller flareups since Hamas seized control of Gaza in 2007 from the internationally recognized Palestinian Authority.

The bitter enemies have been conducting indirect negotiations through Egyptian, UN and Qatari mediators aimed at easing an Israeli blockade of the territory in exchange for quiet and a halt to rocket fire.