The early Saturday strikes, which come on the 33rd day of a massive Israeli assault that has left 1,899 Palestinians dead and more than 9,837 injured, come as negotiations between Palestinian and Israeli delegations stalled, despite reports Friday that both side were close to an agreement.
Egypt, which is mediating between Israelis and Palestinians, insisted negotiations were making progress and urged a new truce but Israel recalled its delegation and warned it would not negotiate under fire.
The head of the Palestinian delegation in Cairo said they were committed to achieving a truce.
"We told the Egyptians (mediators) we are sitting here to achieve a final agreement that restores the rights" of Palestinians, Azzam al-Ahmed told reporters.
Hamas and the Islamic Jihad group had rejected another 72-hour truce, accusing Israel of stalling.
"There had been an agreement on the vast majority of matters that are important to the Palestinian people, but some limited points remained undecided, a matter that should have led to an acceptance to renew the ceasefire," the Egyptian foreign ministry said.
Hamas and Palestine Liberation Organization officials have insisted that Israel end its eight-year siege on the Gaza Strip, release dozens of prisoners whom Israel has re-arrested that were released in 2011 as part of the Shalit exchange, the re-opening of a seaport and airport in Gaza, and the creation of a safe passage between the West Bank and the Gaza Strip.
Despite withdrawing all its troops from Gaza by the time the truce began on Tuesday, Israel has retained forces along the border, ready to resume attacking Gaza.
NTJ/MB