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Israel's military said Monday it downed a drone along its southern coastline, and fired two deadly airstrikes into the Gaza Strip, in its week-long campaign against Islamic militants.

The drone came from Gaza and was shot down by a Patriot surface-to-air missile near the southern city of Ashdod, the military said. It did not say what the drone was carrying and there was no immediate confirmation from Gaza on the use of unmanned aircraft.

Monday’s Israeli airstrikes killed four more Palestinians in the coastal strip, in the southern city of Khan Younis, according to officials from the city's European Hospital.

The officials said Saddam Moamar, his wife Hanadai, and his father Mousa were killed by an airstrike that hit their house. Their neighbor, Maher Abu Mor, was killed in another airstrike while standing on the rooftop of his home, the officials said, speaking on condition of anonymity because they were not authorized to talk to media. It was not immediately clear why their homes were targeted.

Israel began its campaign against militants in the Hamas-controlled Gaza last Tuesday, saying it was responding to heavy rocket fire from the densely populated territory.

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    The fighting began after three Israeli teenagers were kidnapped and found dead in the West Bank on June 30. Hamas did not claim responsibility for the murders, but praised them. Days later, a Palestinian teenager was found dead, sparking days of violent protests in Arab areas of Jerusalem and northern Israel.

    Israel charged three Jews with the kidnapping and killing of the Palestinian teen Monday. Police spokesman Micky Rosenfeld says the three appeared before a court and admitted to abducting 16-year-old Mohammed Abu Khdeir and setting him on fire. Rosenfeld says they also re-enacted the murder.

    The detention of the three main suspects in the case, a 29-year-old man and a pair of 17-year-olds, was extended until Friday as they appeared before a court, officials said.

    Abu Khdeir was taken on July 2 near his home in east Jerusalem and his charred body was later found in a forest. Israel's Shin Bet security service says the suspects, whose names were not released, were motivated by revenge after the kidnapping and killing of the three Israeli teens.

    Monday's strike against Israel introduces the use of drones with an offensive capacity, which could potentially inflict significant casualties -- something the rockets from Gaza have failed to do, largely because of the success of the Israeli military's 'Iron Dome' air defense system shooting them down.

    The use of the unmanned drone marked a new and unexpected tactic by Hamas, which has never before acknowledged having such weapons. Although it was quickly shot down, the drone represented a new level of sophistication for the militant group.

    In a statement to media, Hamas claimed it launched three drones at Israel on Monday, though the military insisted there was only one. Hamas released a video of what it said was the aircraft, about five yards long, with each wing holding two unidentified missiles. The veracity of the video could not be independently confirmed.

    Drones can refer to a range of unmanned aircraft, ranging from rudimentary airplanes to advanced aircraft capable of firing weapons or conducting sophisticated surveillance missions.

    Hamas said it has developed two types of drones -- one for intelligence gathering, and one for delivering munitions. It also said it lost contact with one of the drones and that the targets included the Israeli Defense Ministry compound in Tel Aviv.

    It was the first time the militant group publicly acknowledged it has drones in its arsenal.

    In addition to the drone, the Israeli Defense Forces (IDF) says that militants have launched at least 1,000 rockets at Israeli cities in the six days since Israel launched "Operation Protective Edge," a bid to halt such attacks. No Israeli fatalities have been reported, though a teenage boy was seriously injured by rocket shrapnel in the town of Ashkelon on Sunday.

    The military says that due to years of generous Iranian shipments, thousands of rockets remain in Gaza, and there is no quick way to eliminate the threat. The army says Hamas has an arsenal of some 10,000 rockets, including longer-range, foreign-made weapons capable of reaching virtually anywhere in Israel. The current round of fighting has seen air-raid sirens sound in Jerusalem, Tel Aviv and Haifa, Israel's three largest cities.

    Israeli analysts say that most of the remaining long-range rockets are believed to be stashed beneath residential buildings, and that the only way to completely remove the threat would be to re-conquer Gaza, from which Israel withdrew in 2005, and stay there for a lengthy period. Such a scenario would carry great risk, and Israeli leaders are wary.

    Israeli Prime Minister Benjamin Netanyahu said Sunday that the current Israeli operation could last for "a long time" and that the military was prepared "for all possibilities." That includes a wide-ranging Gaza ground operation, which would likely cause heavy casualties in the coastal strip.

    The Palestinian Health Ministry in Gaza says 175 people have been killed by Israeli airstrikes, though it is not clear how many are civilians and how many are operatives of Hamas or other militant groups.

    The IDF says its goal is to inflict so much pain on Hamas that it will be deterred from attacking Israel again — just like Hezbollah guerrillas in Lebanon have largely remained on the sidelines for the past eight years.

    Military spokesman Lt. Col. Peter Lerner said the military estimated 20 percent of the rockets in Gaza have either been fired or destroyed by Israel. Besides diminishing Hamas' future capabilities, he said Israel's assaults were mostly aimed at convincing Hamas never to try it again.

    "When they come out of their bunkers and they look around, they are going to have to make a serious estimation of whether what they have done was worth it," he said. "And people will look in their eyes and say 'Why did you do this? What did you gain from this?'"

    But Netanyahu is coming under increasing international pressure to end the operation soon. On Sunday, U.N. Secretary-General Ban Ki-moon called for an immediate cease-fire while U.S. Secretary of State John Kerry voiced American "readiness" to help restore calm. Egypt, a key mediator between Israel and Hamas, continued to work behind the scenes to stop the conflict.

    The European Union said Monday it was in touch with ``parties in the region'' to press for an immediate cease-fire in Gaza, Reuters reported.

    ``We call on all sides to exercise maximum restraint, to avoid casualties and to return calm. We are in contact with parties in the region to do their utmost to achieve an immediate cease-fire,'' EU foreign policy spokeswoman Maja Kocijancic told reporters.

    Hamas has sent signals it may be ready to consider a cease-fire, but appears to be waiting for some tangible military or diplomatic achievement before moving ahead on that front.

    Also Monday, a 21-year-old Palestinian was killed during confrontations with Israeli soldiers in the West Bank village of Samoa, near Hebron, Palestinian health officials said. Residents of the village said soldiers opened fire at a group of Palestinians who were throwing stones at them. The officials and the villagers spoke on condition of anonymity because they were not authorized to talk to media.

    The Israeli army confirmed the death and said it was looking into the incident.

    The Associated Press contributed to this report.