Israeli Prime Minister Benjamin Netanyahu has said Israel will keep up its military campaign in the Gaza for as long as needed and with as much force as necessary.
Mr Netanyahu said that all options were "on the table" to achieve that mission.
He said: "From the beginning, we promised to return the quiet to Israel's citizens and we will continue to act until that aim is achieved."
Mr Netanyahu said: "We will take as much time as necessary, and will exert as much force as needed and all options are on the table to return peace to the citizens of Israel."
He also pledged to do whatever necessary to bring home 23-year-old soldier Hadar Goldin.
Israel believes he was captured by Palestinian militants during an ambush in southern Gaza early yesterday.
The soldier's mother made an appeal demanding there be no troop withdrawal until her son is found.
Mr Netanyahu said troops would complete the mission of destroying a complex network of tunnels used by militants to infiltrate southern Israel before deciding on its next security objectives.
Some Israeli ground forces withdrew from Gaza, two Israeli television stations reported.
The military said it was close to achieving its main war goal of destroying Hamas cross-border tunnels.
Asked about the reports, an Israeli military spokesman said she could not comment on troop deployments.
Israel did not send envoys to Gaza truce negotiations in Egypt today as planned.
It accused enemy Palestinian Islamists of misleading international mediators.
"Hamas is not interested in an accommodation," the official said on condition of anonymity.
An Egyptian-brokered ceasefire broke down within hours yesterday, with Israel and Hamas trading blame.
Egypt's President said this morning a ceasefire plan proposed by his country offered the chance to end the Gaza conflict, but warned that lost time further complicated matters.
Gaza officials say at least 1,654 Palestinians, mostly civilians, have been killed since the Israeli offensive started on 8 July.
63 Israeli soldiers have died, and three civilians have been killed by Palestinian rockets in Israel.
Hamas leaders have said any Egypt-brokered deal must include an end to Israel's blockade of Gaza.
They called for Cairo to ease curbs at its Rafah crossing with Gaza.
This was imposed after the military ousted President Mohammed Mursi, a year ago.
The planned 72-hour break in fighting announced by US Secretary of State John Kerry and UN Secretary-General Ban Ki-moon hours before it was due to take effect early yesterday was the most ambitious attempt so far to end more than three weeks of fighting.
Protests across Ireland
Meanwhile, in Dublin, up to 4,000 people have turned out in Dublin city centre for a rally sympathising with the Palestinian people.
The organisers of the rally, the Ireland Palestine Solidarity campaign, say it has also been staged to protest over the Government's decision to abstain from voting.
The Government abstained from voting in a United Nations resolution calling for a commission of inquiry to be set up to investigate Israel's action in Gaza.
Protesters made their way down O'Connell Street from the Garden of Remembrance to the Department of Foreign Affairs on St Stephen's Green where speeches were made.
It was one of a number of pro-Palestinian rallies being held across the country.
In Galway, up to 160 protesters marched from Eyre Square to the Spanish Arch in Galway city.
Leaders of the protest called for the expulsion of the Israeli ambassador to Ireland.
Minister for Foreign Affairs Charlie Flanagan said that we must hope that intensive diplomatic efforts will be successful in reinstating a ceasefire.
He appealed to all sides to show restraint.
A spokesperson for the Israeli Embassy said that people who protest across the country do not seem to have concern for the Palestinian people in Gaza.
He said "because if they did, they would be protesting against Hamas which is inflicting terror on its people".