Israeli Prime Minister Ehud Olmert has said Israel is not ready to stop its offensive against Hezbollah in Lebanon.
Fighting has continued across the Israeli-Lebanese border
"The fighting continues. There is no ceasefire and there will not be any ceasefire in the coming days," he said.
Mr Olmert apologised "for the pain caused" to Lebanese civilians, but said Hezbollah had suffered a severe blow.
In late-night discussions, Mr Olmert's security cabinet was reported to have approved plans to widen Israel's ground offensive in Lebanon.
Israel and Hezbollah traded fire on Monday, less than a day after Israel declared a partial halt to air strikes on south Lebanon.
Israeli warplanes struck several targets, killing a Lebanese soldier near the city of Tyre. Israel expressed regret over the death, saying it believed the vehicle was carrying a senior Hezbollah official.
Israeli officials said the pause was to allow time for an investigation into the Qana attack and for the UN to evacuate civilians from the area. However Israel reserved the right to continue targeting militants preparing attacks.
Fighting has also continued on the ground in southern Lebanon, with the villages of Taibe, Kila and Adasya coming under Israeli artillery fire.
Hezbollah fired two shells which landed on the outskirts of the Israeli border town of Kiryat Shmona, causing no injuries.
Israel's military said Hezbollah also hit an Israeli tank near Taibe, wounding three soldiers.
In other developments:
- The UN Security Council extended the mandate of the UN Interim Force in Lebanon (Unifil) for one month
- New York-based group Human Rights Watch accused Israel of committing war crimes by carrying out what it called an indiscriminate bombing campaign in Lebanon
- Syrian President Bashar al-Assad told his country's army to raise its state of readiness in the face of "Israeli aggression", in a long-planned annual speech to the Syrian armed forces
- Lebanon observed a national day of mourning following the deaths in Qana, with many banks and public buildings closed
Speaking in Tel Aviv, Mr Olmert said Israel's campaign would continue until it achieved its goals.
"We will end it when the threat over our heads is removed, when our kidnapped soldiers return to their homes and when we can live in security," he said.
Israel began its offensive in Lebanon after Hezbollah militants captured two Israeli soldiers in a cross-border attack on 12 July. It is also fighting Palestinian militants in Gaza to secure the release of an Israeli soldier held captive there since 26 June.
Mr Olmert said Israel was "not fighting against the Lebanese people. We do not want to topple their government.
Later on, a statement from Mr Olmert's office said he told UK Prime Minister Tony Blair a ceasefire could be implemented "immediately" after the deployment of an international stabilisation force in Lebanon.
Mr Olmert's televised comments came hours after US Secretary of State Condoleezza Rice said the US would seek a UN resolution calling for a ceasefire this week.
US President George W Bush meanwhile said on Monday that the UN had to address the "root causes of the problem".
"We want there to be a long-lasting peace, one that is sustainable," he said after meeting Cuban-American business leaders in Miami, Florida.
Israeli Defence Minister Amir Peretz described the 48-hour cessation of air strikes, from 0200 Monday (2300 GMT on Sunday) as a "humanitarian gesture".
At least 54 people, many of them children, were killed in Qana on Sunday when the house in which they were sheltering was hit by Israeli warplanes - the deadliest such raid since hostilities began.
The BBC's Jim Muir in Qana says the scene is one of utter desolation. He says Qana has become a ghost village like many others on the road up from the southern city of Tyre, with women and children now a rare sight.
After nearly three weeks of fighting, about 750 people - mainly civilians - have been killed by Israeli action, according to Lebanon's health minister.
A total of 51 Israelis, including at least 18 civilians, have also been killed in attacks by Hezbollah.
[Note: The number of people killed in the Israeli bombing of Qana was later revised. The Washington based human rights group Human Rights Watch investigated the incident and issued a report on 3 August saying that 28 people were known to have died, while 13 people were missing.]