The Israel Defense Forces moved tanks and artillery units towards Gaza, positioning them in advance of any order from the cabinet to invade the densely populated enclave, with nearly two million people crammed into an area of less than 200 square miles. The IDF also called up an undisclosed number of reservists for duty.
The military mobilization was the largest on the border of Gaza since Israel's last major attack on the Palestinian territory, eight days of bloody bomb and missile strikes in November 2012.
An Israeli military spokesman claimed the sites targeted by bombs and missiles were linked to Hamas, the Islamic party that has ruled Gaza since it won elections in 2006. The Israeli government has declared Hamas responsible for the kidnapping and murder of three Israeli teenagers in the West Bank, although that territory is controlled by the secular Palestinian party Fatah, with Israeli support.
The killing of the three teenagers, whose bodies were found on June 30 outside Hebron, is being used as a pretext by Prime Minister Benjamin Netanyahu to escalate tensions with Hamas and threaten an invasion or re-occupation of the Gaza Strip. Israeli military forces and settlers were withdrawn from Gaza in 2005.
Thursday's bombing was the latest in a series of tit-for-tat exchanges, with Israeli jets dropping bombs or firing missiles at targets in Gaza, while Palestinian militants launch primitive unguided rockets from Gaza at nearby Israeli towns, particularly the border town of Sderot.
The Israeli attacks, using high-tech weaponry, much of it supplied by the United States, are far more destructive and lethal. On Tuesday, Israeli air strikes hit 34 targets in Gaza, after attacks over the weekend.
Bombs and missiles in Gaza have been combined with brutal military-police operations on the West Bank, where 500 Palestinians were arrested, dozens injured, and six killed in the four weeks since the kidnappings on the West Bank.
Tensions on the West Bank exploded Wednesday after the killing of a Palestinian youth, 16-year-old Muhammad Hussein Abu Khudair, who was abducted from the street outside his home in East Jerusalem, apparently by ultra-right Jewish settlers vowing "revenge" for the killing of the three Israeli youth. Khudair's body was found miles away, badly burned and bearing marks of violence.
Thousands of Palestinians took to the streets Wednesday in East Jerusalem in response to the news of Khudair's murder, throwing rocks, bottles and firecrackers at police and setting up barricades. The neighborhoods of Shuafat and Beit Hanina, where the violence was concentrated, were relatively quiet on Thursday, as the residents prepared for the funeral service, and Israeli troops sealed off access to that part of the city.
Late Thursday, the Khudair family said the funeral was postponed until Friday because of the delay in conducting an autopsy in Tel Aviv, where a Palestinian doctor was to observe the procedure.
Elsewhere in Jerusalem, protesters threw rocks and built barricades of burning tires. Israeli police fired stun grenades but otherwise did not directly engage the protesters.
Israeli police officials claimed that despite an intensive investigation, "the motive for the murder cannot be determined at present." Eyewitnesses described the attackers as Jewish, however, and Palestinian officials have charged that the attackers were Israeli extremists.
While witnesses supplied police with the license plate number of the vehicle used by the kidnappers, the police have not publicly identified the killers.
The murdered youth's family criticized police inaction. Hussein Abu Khudair, Muhammad's father, declared: "If things were different, and an Arab kidnapped an Israeli, it would have been uncovered in moments."