Fighting has resumed in Gaza following a three-hour ceasefire.
Two Palestinians were killed in an Israeli strike on the eastern Gaza City neighbourhood of Zeitun.
Bombing had been temporarily suspended to allow the passage of humanitarian aid into the territory.
Israel earlier announced that bombing would be suspended between 1pm and 4pm (11am-2pm Irish time).
Hamas responded by saying no rocket attacks would be made during the same period.
However, Israeli Defence Force spokesmen said later it would not happen 'each day', as had been reported earlier.
'I can confirm that there is a cessation of offensive activities at this time in order to facilitate humanitarian transfers and we will enable the population to resupply themselves and facilitate the work of the NGOs,' said an Israeli spokesperson.
However, an Israeli spokesperson warned the army would respond to any fire including rocket fire.
Israel pounded Gaza with artillery shells and air missiles again this morning.
An air strike killed a Palestinian man and wounded three others in Zeitun, where some of the heaviest fighting has occurred since Israeli troops invaded on Saturday.
Clashes occurred in Zeitun, and there were reports of air strikes on the southern cities of Khan Younis and Rafah.
Read Tony Connelly's feature about the media war in Gaza
Irish struggle to escape conflict
The Department of Foreign Affairs says it has been unable to help around 20 Irish citizens and their families to leave Gaza because of ongoing security concerns.
According to a spokesperson for the Department, it is issuing Irish visas to family members of Irish citizens in Gaza in an attempt to bring them to safety in Ireland.
One Irish citizen, five-year-old Basil Natil, is in Gaza with his mother and three sisters aged 10, eight and three.
His father, based in the UK, was concerned that visas were initially being offered to only Basil and his mother, but the DFA say that visas are now being offered to all family members in Gaza.
School strike totally unacceptable: Ban
The latest fighting followed Israeli strikes yesterday on three UN-run schools that killed at least 48 people, prompting growing calls for an immediate ceasefire.
UN Secretary General Ban Ki-moon said he was ‘deeply dismayed’ by the strikes on the schools and called them ‘totally unacceptable'.
Egypt's President and veteran Middle East peace mediator, Hosni Mubarak, is pushing for an immediate ceasefire and has invited Mr Olmert for talks on his proposal in Cairo.
Mr Mubarak said Israelis and Palestinians need ‘an urgent meeting to reach arrangements and guarantees that would not allow the repeat of the current escalation'.
Such guarantees would include ‘securing the borders and ... opening of the border crossings and lifting the siege'.
French President Nicolas Sarkozy, whose country currently holds the UN Security Council presidency, said a resolution on Gaza would ‘complicate’ the task of achieving peace.
Libya later submitted a new draft resolution demanding an immediate and permanent ceasefire to be respected by both parties.
A Hamas delegation is already in Cairo for talks on the crisis.
Egypt brokered a six-month truce that ended on 19 December.
Hamas refused to renew the deal, accusing Israel of reneging on it by not relaxing the crippling blockade of Gaza it first imposed when the Islamists seized control of the territory in 2007.
Mr Olmert earlier said the rocket attacks and weapons smuggling from Egypt into Gaza must end before Israel halts its offensive.
