Israel unleashed new airstrikes on Gaza early Tuesday, hitting the highrise home of a Hamas field commander and two border tunnels dug by militants, as Hamas and other armed groups fired dozens of rockets toward Israel. The escalation in the conflict was sparked by weeks of tensions in contested Jerusalem. Since sundown Monday when the cross-border attacks began, 24 Palestinians — including nine children — were killed in Gaza, most by airstrikes, Gaza health officials said. The Israeli military said 15 of the dead were militants. During the same period, Gaza militants fired more than 250 rockets toward Israel, injuring six Israeli civilians in a direct hit on an apartment building. In a further sign of rising tensions, Israel signalled it is widening its military campaign. The military said it is sending troop reinforcements to the Gaza border and the defence minister ordered the mobilization of 5,000 reserve soldiers.