Israeli warplanes targeted homes of Hamas officials early Wednesday, security sources said, as a campaign against Gaza militants entered day nine with no sign of an end to hostilities, AFP reported.
After a brief respite, Israel had resumed Tuesday its punishing air campaign against the Palestinian territory, which has killed more than 200 people, as international efforts towards a ceasefire collapsed.
Israel's Prime Minister Benjamin Netanyahu warned the army would "expand and intensify" its operation after Hamas snubbed the Egyptian ceasefire proposal.
The first major strike on Wednesday hit the western Gaza City home of senior Hamas figure Mahmud al-Zahar, flattening the building, security officials said, but witnesses said the house had been empty.
Separate strikes in Gaza City and Jabalia in the north targeted the homes of at least three other Hamas officials, with no immediate reports of casualties.
Wednesday's first deadly strikes, in the southern city of Rafah, killed three men, one of whom witnesses said was an Islamic Jihad militant, bringing the death toll in Gaza to 200.
The early morning raids came after the first Israeli fatality from a total of nearly 1,000 rockets fired into the Jewish state by Gaza militants.
The civilian man, 37-year-old Dror Hanin, was killed in a rocket attack on an Israeli position near the Erez crossing with Gaza late Tuesday after delivering food to soldiers, medics said.
Israel's security cabinet had said early Tuesday it would accept an Egyptian proposal for a ceasefire to begin at 0600 GMT.
But Hamas officials said they had not been consulted on the proposal and would not halt fire without a full-fledged deal including Israeli concessions.
The movement's armed wing continued to fire dozens of rockets into Israel after the truce deadline, sending tens of thousands scrambling for cover.
At 1200 GMT, the Israeli army announced it was resuming air strikes, after militants fired 47 rockets from Gaza.
"This would have been better resolved diplomatically... but Hamas leaves us no choice but to expand and intensify the campaign against it," Netanyahu said Tuesday.
Later, the Israeli army said it was sending messages to residents of parts of eastern and northern Gaza, "requesting them to evacuate their homes for their own safety" ahead of new strikes.
The army issued similar messages to north Gaza residents on Sunday, causing the exodus of 17,000 people who took shelter in United Nations schools.
Hamas's Ezzedine al-Qassam Brigades armed wing had almost immediately rejected the Egyptian proposal for a truce to be followed by talks.
Hamas spokesman Sami Abu Zuhri said the movement had not been consulted on the truce bid, and called the idea of halting fire before agreeing on terms "unacceptable".
A top member of Hamas's exiled politburo, Mussa Abu Marzuq, sounded a more cautious note, saying the movement had no official position on the proposal and discussions were continuing.
Hamas has said it wants the end of Israel's blockade of Gaza and the opening of the Rafah border crossing with Egypt as part of a truce deal.
It also wants Israel to free Palestinians it rearrested after releasing them in a 2011 exchange for an Israeli soldier held by Gaza militants for more than five years.
In his remarks on Tuesday evening, Netanyahu hit back at domestic critics of his decision to accept Egypt's proposal.
"These are moments when decisions must be made coolly and with patience, not hastily or noisily," Netanyahu said.
The Israeli premier also fired deputy defence minister Danny Danon, a firebrand member of his Likud party, who was a vocal critic of him during the operation.
Cairo's proposal was announced overnight, and urged both sides to halt the violence and travel to Egypt for talks.
Palestinian president Mahmud Abbas was due in Cairo on Wednesday, but it was unclear if Hamas officials there were continuing to discuss the truce bid and if Israeli officials would also travel to Egypt.
The proposal had won support from Western governments with US President Barack Obama saying he was "encouraged" by Egypt's efforts and hoped to see calm restored.
And even after the violence resumed, US officials said Secretary of State John Kerry remained engaged and had spoken late Tuesday with Netanyahu and other regional leaders about the crisis from his plane on his flight back to Washington.
Israel launched Operation Protective Edge before dawn on July 8, hitting Gaza with an intensive air and artillery bombardment aimed at stamping out rocket fire.
Since then, 960 rockets have hit israel, while another 215 have been intercepted by its Iron Dome air defence system, the army said.