The Lebanese army said on Wednesday it found and deactivated more rockets in an area from where a similar device had been fired into Israel, Reuters reported.
An army statement said troops found four 107-mm rockets in the garden of a partly built house as they searched the area a day after a rocket fired from the southern village of Houla hit the northern Israeli border town of Kiryat Shmona.
Israeli artillery fired into Lebanon after Tuesday's rocket attack. There were no casualties or damage on either side.
UNIFIL, the peacekeeping force in southern Lebanon that was expanded after the 2006 war between Israel and Hezbollah guerrillas, said the rocket attack was a serious violation of U.N. Security Council resolution 1701, which halted the war.
"This was the fifth such incident this year. Such attacks are evidently aimed at provoking renewed hostilities to undermine the security and stability in the south," said UNIFIL spokeswoman Yasmina Bouziane.
"It is also a cause of concern that the IDF (Israel Defense Forces) returned fire with artillery shells into Lebanese territory."
Earlier, UNIFIL commander Major General Claudio Graziano inspected the area where the four rockets, three of which were rigged for launch, had been found.
There was no immediate claim of responsibility for the attack.
A militant group claiming links to al Qaeda said it was responsible for firing two rockets from Lebanon across the border last month, saying it was retaliating against Israel for blockading the Palestinian enclave of Gaza and preventing worshippers from praying at the al-Aqsa mosque in East Jerusalem.
Israel's Industry and Trade Minister Binyamin Ben-Eliezer blamed a Palestinian group for Tuesday's incident.
"What I know, and what has been reported to me so far, this is (the work of) a Palestinian organization which is trying to inflame the region. For now, Hezbollah understands that it would not be right for it strategically to open a front with Israel, because they know we would respond," he told Israeli Radio.
Army commander Jean Kahwaji said Lebanon would not let those behind such attacks drag it into a battle with Israel.
The border has remained mostly quiet but tense since the 34-day Israel-Hezbollah war. Israel and Lebanon accuse each other of violating the U.N. resolution that ended the conflict.
Israel has complained about two blasts in July and October involving alleged arms depots in southern Lebanon, as well as the occasional rocket attacks, which have been widely blamed on fringe militant groups rather than Hezbollah.
Lebanon has objected to near-daily Israeli overflights and suspected espionage activities. A U.N. investigation into explosions in the south last week indicated that Israel had planted spy devices and then blown them up.