Israel and Hamas have resumed fighting despite tentative offers to extend a humanitarian truce since the end of an initial 12-hour temporary ceasefire on Saturday.
Israel's Prime Minister Benjamin Netanyahu on Sunday accused Hamas of violating a ceasefire that it had itself called and vowed that Israeli operations in Gaza would continue.
"They are violating their own ceasefire. Under these circumstances, Israel will do what it must do to defend its people," Netanyahu told the news network CNN.
Earlier, the Palestinian Islamist movement Hamas agreed to halt firing from 11:00 GMT in response to a request from the United Nations.
Speaking to FRANCE 24 from Gaza City, journalist Jesse Rosenfeld said a Hamas spokesman had told him that the movement had accepted the latest truce specifically because it had been brought to them by the UN, which had not been the case before.
On Saturday night, Israel endorsed a separate ceasefire plan promoted by Egypt that has not been accepted by Hamas, but Netanyahu was dismissive about Sunday's latest UN truce call.
Netanyahu told CNN that Israeli forces would continue operations to attempt to dismantle Hamas' cross-border tunnel network and destroy its stocks of rockets.
"Israel is doing what any other country would do and the US would do if any percent of your country were under fire and you have 60 or 90 seconds to get to a bomb shelter."
"I would say we want to stop firing rockets for sure. We want to dismantle the tunnels, the terror tunnel network we uncovered," he said. " I don't know if we'll have 100 percent success. Our soldiers are dealing with it now."
Rosenfeld said bombardment by Israel's air force and navy was continuing on Sunday afternoon.
Conditions for truce
FRANCE 24's Jerusalem correspondent Gallagher Fenwick remarked that recent diplomatic efforts to bring an end to the latest fighting, which has left more than 1,000 people dead after 19 days, had failed to include the main actors in the confrontation.
"There were no Egyptians, no Palestinians, and no Israelis" at Saturday's meeting of international foreign ministers on the Gaza crisis in Paris, he said.
The Israeli newspaper Haaretz has leaked the latest ceasefire proposal, drafted by US Secretary of State John Kerry in Paris. "Many Israeli papers are condemning it, saying Kerry has turned its back on Israeli demands and acceded to Hamas's," Fenwick reported.
On the Hamas side, tactical considerations may have dictated the preference for the terms of the UN-sponsored proposal of a daytime truce.
"This would allow people to get out, resupply, let out some steam and hunker down again" during the day, said Jesse Rosenfeld in Gaza.
"The fact is that Hamas has been striking far more Israeli casualties at night," he added. "It is more beneficial to them to have ceasefires during the day, than it is during the night when they carry out a far more intense guerilla campaign."