Several rockets have been fired from Lebanon into northern Israel, as fighting and rocket fire continues in the south and Gaza.
Air raid sirens in Israel - this time in the north, where rockets were fired from Lebanon.
In southern Lebanon, U.N. peacekeeping forces Deputy Spokesman Andrea Tenenti, confirmed the firing.
"We can confirm that at least three rockets early this morning were fired into Israel from about seven-kilometers east of Naqoura in south Lebanon," he said.
The rockets hit in and around the Israeli border town, Nahariya.
A home for the elderly in Nahariya was hit and two people were reported to have been slightly injured.
Israel responded with artillery fire. Lebanese security officials say they are investigating the incident.
Lebanonese Prime Minister Fuad Siniora condemned the attack as an attempt to undermine stability and also condemned the Israeli response.
There was no immediate claim of responsibility and initial indications were that a splinter Palestinian group in Lebanon may have been responsible and not necessarily the militant Shiite group Hezbollah, with whom Israel fought a bloody war in 2006.
There is no indication that the rocket fire from Lebanon signals the opening up of a second front of fighting for Israel. But that possibility is something that has Israeli officials concerned.
When he announced the beginning of the ground offensive in Gaza, Defense Minister Ehud Barak said Israel would keep close watch on its northern border.
"We hope the situation will remain calm. Nevertheless, we are ready and alert to face any unwarranted development in that area," said Barak.
Fighting continued in Gaza, including more than 60 Israeli air strikes reported overnight. Palestinian militants also continue to fire rockets into southern Israel.
Israel announced another suspension of fighting for three hours to allow distribution of food, fuel and other humanitarian goods in Gaza and to allow Gaza residents to get supplies and medical help. It is the second day in a row of such a lull in fighting, but aid officials say a three-hour suspension is not enough.
Israel is sending a senior envoy to Egypt to talk about a possible ceasefire. Representatives from Hamas and the Palestinian Authority were also expected to meet separately, in Egypt, to discuss an end to the fighting in Gaza.