GAZA CITY, July 10 - Israeli strikes on Gaza killed 31 people on Thursday as a major air campaign entered its third day, with most of the bloodshed in the southern city of Khan Yunis. The deaths raised to 82 the overall number of Gazans killed since Israel launched Operation Protective Edge early on Tuesday to halt cross-border rocket fire by militant groups. Most deaths occurred place in Khan Yunis with a strike at about 1:00 am (2200 GMT) hitting a cafe where football fans were watching the World Cup semi-final between Argentina and the Netherlands. Nine people were killed, and at least 15 wounded, emergency services spokesman Ashraf al-Qudra said. An hour later, Israeli warplanes struck two houses elsewhere in the city, killing four women and four children. Another strike on the city killed a 19-year-old man and his 75-year-old father. A four-year-old child who was also injured in one of the strikes on Khan Yunis succumbed to her injuries during the day. In central Gaza, a man was killed in a strike on Nusseirat refugee camp. In Zeitun, east of Gaza City, a missile killed a man on a motorbike in the late afternoon. Another man was killed in a strike on the northern town of Jabaliya at around the same time. Hours earlier, a strike on a car elsewhere in Jabaliya killed three men, all of them members of Islamic Jihad's armed wing, the Al-Quds Brigades, a fellow militant told AFP. The army also identified them as Islamic Jihad militants involved in firing of rockets at Israel. It named one as Allaa Abd al-Nabi and said he played "an active part in the current escalation" and was responsible for firing long-range rockets over the border. Earlier, a strike on a car in the west of Gaza City killed a 35-year-old man and two others. And in the north, a five-year-old boy was killed when an Israeli missile struck the town of Beit Lahiya. Medics said a 22-year-old man died of injuries sustained in northern Gaza, without specifying when. Another man who was badly wounded in a raid east of Gaza City a day earlier also died of his wounds, taking Wednesday's toll to 30 people. On Tuesday, the first day of the operation, 21 people were killed. The army said it had hit more than 300 targets overnight, raising the total number of strikes just over 48 hours to 750, in Israel's largest military operation in Gaza since November 2012. On Tuesday, 117 rockets fired by Gaza militants struck Israel, and 29 were intercepted by the Iron Dome anti-missile system. Another 90 rockets hit Israel on Wednesday, and 24 were intercepted. On Thursday, 15 rockets struck Israel, while another seven were intercepted, army figures show. There have been no Israeli deaths so far, but Hamas has launched waves of rockets across central Israel that have triggered sirens in cities as far from Gaza as Tel Aviv, Jerusalem, and Haifa.