<span style="color: #222222;">Israel conducted dozens of air strikes on the Gaza Strip today after Palestinian militants fired barrages of rockets at southern Israeli cities.</span><br />'' <span style="color: #222222;"> </span><br />'' <span style="color: #222222;">The pre-dawn raids on Gaza were some of the heaviest seen since the fighting began a week ago.</span><br />'' <span style="color: #222222;"> </span><br />'' <span style="color: #222222;">Israel said it hit facilities belonging to the militant group Hamas and several commanders' homes, but main roads and power lines were also damaged.</span><br />'' <span style="color: #222222;"> </span><br />'' <span style="color: #222222;">There were no immediate reports of casualties following the strikes. The Israeli military said more than 50 warplanes conducted a 20-minute attack on the Gaza Strip shortly before dawn.</span><br />'' <span style="color: #222222;"> </span><br />'' <span style="color: #222222;">They struck 35 'terror targets' and destroyed more than 15km of an underground tunnel network belonging to Hamas, it added.</span><br />'' <span style="color: #222222;"> </span><br />'' <span style="color: #222222;">The military also said it had hit the homes of nine high-ranking Hamas commanders. Hamas, which controls Gaza, began firing rockets  triggering retaliatory air strikes.</span><br />'' <span style="color: #222222;"> </span><br />'' <span style="color: #222222;">Israel says more than 3,000 rockets have been fired into the country over the past week.</span><br />'' <span style="color: #222222;"> </span><br />'' <span style="color: #222222;">Rocket warning sirens sounded again, in several areas around southern Israel today. One rocket hit an apartment building in the city of Ashdod and several people were reportedly hurt.</span><br />'' <span style="color: #222222;"> </span><br />'' <span style="color: #222222;">Palestinian officials in Gaza, meanwhile, said the overnight strikes had caused widespread power cuts and damaged hundreds of homes and other buildings.</span><br />''