Two rockets fired from Lebanon slammed into northern Israel on Monday, the IDF said.
There were no immediate reports of casualties from the attack. It was the fourth time rockets have been fired from Lebanon since the start of a week-old Israeli offensive against Palestinian militants firing rockets at Israel from Gaza.
The IDF responded with artillery fire into southern Lebanon after the attack, which came as Israel and Hamas locked horns in the Gaza area, with hundreds of rockets raining down on Israel.
At roughly 6 pm, another rocket, this time fired from Syria, landed in a town in the north of the Golan Heights. No injuries were reported as a result of the attack and the IDF again, returned fire.
The Lebanese rockets were fired from the area around the southern city of Tyre, Lebanese security sources said. Israel responded by firing at least 15 shells, one source said.
An Israeli military spokesman said the army "fired a salvo of shells and flares towards the launching site in Lebanon".
On Friday, Lebanese authorities said they had arrested a man suspected of being behind one of the rocket attacks. The national news agency said he was a member of a "fundamentalist group" but did not give details.
The rocket fire followed three previous attacks of similar nature from Lebanon. A little after midnight Sunday, rocket sirens were heard in Nahariya, Shlomi and other communites in the Western Galilee after no less than 6 rockets were fired at Israel from Lebanon.
They all fell in open areas and no damages were sustained. Lebanese media outlets reported Monday that the Lebanese army located the two launchers from which rockets were fired from south Lebanon at Israel overnight Sunday.
Earlier Sunday, a false alarm was sounded in the city due to rocket fire towards the area of Haifa.
Meanwhile, Hamas officials in Lebanon commented on the rocket salvo on Israel from Lebanon late on Saturday and said the group had no role in the attack, and that it had nothing to do with a statement in the name of its armed wing that claimed responsibility for it.
Another incident saw three rockets fired from Lebanon that hit open areas near Nahariya in northern Israel on Saturday evening. Israel responded with artillery fire. There were no casualties.
Were Hezbollah behind the attack in question, it would have marked its first such military action across the Lebanese-Israeli frontier.
The attacks from Lebanon coincided with an Israeli offensive on the Hamas-run Gaza Strip that Palestinian officials say has killed some 180 people. Militants in Gaza have fired hundreds of rockets into Israel during the latest hostilities.
A UN peacekeeping force in Lebanon said there had been no immediate claim of responsibility for the attack from Lebanon and urged maximum restraint. UNIFIL, the peacekeeping force, said it had "intensified patrols across the area of operations to prevent any further incidents".
Two Hamas officials in Lebanon said the group was not behind the attack.
Asked about a claim of responsibility issued in the name of the Izz el-Deen al-Qassam Brigades - the Hamas armed wing - Hamas official Osama Hamdan said: "We denied it and said Hamas had nothing to do with this statement."
The claim of responsibility had been circulated in a text message received by journalists in Gaza, the way the Izz el-Deen al-Qassam Brigades often makes such announcements.
A Lebanese security official said investigators had yet to determine who fired the rockets. The main Palestinian factions in Lebanon had told the investigators they were not involved in the attack, the official said.
Roi Kais, Associted Press and Reuters contributed to this report