GAZA/JERUSALEM: Israel today unleashed more airstrikes on Gaza and shot down a drone used for the first time by Hamas militants even as international pressure mounted on both to end the week-long conflict that has killed 175 Palestinians.Although Israel has delayed its ground offensive amid global calls for a ceasefire, the military continued its airstrikes, killing four people today.The Israeli military said that it shot down the drone spotted along the Israeli coastline, near the city of Ashdod.Hamas' military wing said in a statement that it has sent a number of drones on missions inside Israel and would provide more details in due course.About 17,000 people from the Beit Lahiya area in the northern Gaza Strip streamed for protection into UN-run facilities after Israel yesterday warned residents of the area to leave their homes.Israeli warplanes bombarded the vacated area, hitting alleged launch sites and homes of members of extremist groups such as Hamas and Islamic Jihad. The assault was carried out mostly by air, but the Israeli navy also reportedly fired shells from the sea.Despite the concentrated attack, militants continued to fire rockets at a broad swath of Israel. A teenager became the second Israeli civilian to be severely wounded. No Israelis have been killed by the rocket strikes.Israeli air strikes today hit three training facilities of Hamas's military wing and buildings in Gaza city, causing injuries.By this morning, the death toll from nearly a week of Israeli airstrikes reached 175 -- all of them Palestinians -- with more than 1,260 wounded, according to Palestinian health authorities.While the Israeli attacks have killed some militants, around 70 per cent of the fatalities were civilians, according to the United Nations. Of the dead, more than 30 are children, the UN reported.Israel has massed thousands of troops on the border with Gaza amid warnings it is prepared to launch a ground invasion. Israeli commandos carried out their first reported ground incursion yesterday, attacking a suspected rocket launch site.Israel has so far shrugged off international calls for a cease-fire, saying it will continue the offensive as long as the militant group Hamas keeps firing rockets into its territory.Defending Israel's actions, Prime Minister Benjamin Netanyahu said, "We're sorry for any accidental civilian deaths but it's the Hamas that bears complete responsibility for such civilian casualties."