Israeli forces sent tanks into the western side of Gaza's Nuseirat camp Monday in a new incursion into the enclave's central area, and Palestinian medics said Israeli military strikes had killed at least 30 people since Sunday night.Residents said Israeli tanks opened fire as they rolled into that sector of the camp, one of the Gaza Strip's eight historic refugee sites, causing panic among the population and displaced families.With the war in Gaza now in its 14th month, Israel is focusing its operations in the north and centre in what it says is a campaign to stop Hamas fighters waging attacks and to prevent them from regrouping.Tens of thousands of Palestinian residents have been told to evacuate the areas, fueling fears that they may never be allowed to return.In attacks overnight and into Monday, health officials at Al-Awda Hospital in Nuseirat said 20 people were killed in a series of strikes from air and the ground, one that hit a tent encampment.In the northern Gaza town of Beit Lahiya, medics said four people were killed in an Israeli airstrike. Others were killed in Israeli airstrikes in Gaza City.Israeli forces have besieged the three hospitals in and around Jabalia for several weeks and hospital officials have refused orders to evacuate the facilities or leave their patients unattended despite the lack of food, medical, and fuel supplies.The Israeli military accuses Hamas of exploiting Gaza's civilian population for military purposes, a charge the militant group denies.The army sent tanks into Beit Lahiya, Beit Hanoun, and Jabalia camp in northern Gaza over a month ago.Palestinian and United Nations officials say there are no safe areas in the enclave, home to more than 2.1mn people and now largely in ruins.Israel's military campaign has leveled much of Gaza and killed around 43,500 Palestinians, Gaza health officials say.