Two Katyusha rockets fired from Lebanon landed west of the northern Galilee town of Kiryat Shmona at approximately 7 a.m. local time.

No one was wounded and there was no damage reported from the attack.

Security officials said a total of four rockets were launched from southern Lebanon, but two failed to make it across the border, landing inside Lebanon. The report was followed on Sunday morning by a Lebanese report of two rocket falls near Sarda, a village some 10 kilometers from Marj Ayoun near the border with Israel. Lebanese Army troops deployed to the area to investigate.

The IDF said in a tweet on its Hebrew-language Twitter feed that it retaliated for the rocket attack with “massive artillery fire of dozens of shells targeting the source of the [rocket] fire.” Lebanese sources disagreed on the number and targets of the shells fired by the IDF, with Lebanon’s state news agency saying that over 20 shells hit the mountainous, rugged area around the southern Lebanese border area of Rashaya early Sunday. There were no reports of injuries on the Lebanese side.

Meanwhile, Hezbollah’s official Al-Manar news outlet reported four artillery shells targets the southern Lebanese village of Shuba. Lebanese and UN security forces went on high alert following the exchange of fire.

Residents in Kiryat Shmona reported a smoke cloud rising from one of the landing sites on Sunday morning.

“I heard the falls from my house,” Kiryat Shmona Mayor Nissim Malka told Army Radio Sunday morning, describing the explosions as “loud booms.”

“The army is investigating. We’re convening a meeting of the city council,” Malka said.

IDF forces were sweeping the area to locate the fallen rockets.

“This attack from Lebanese soil is an inexcusable, unacceptable blatant breach of Israel’s sovereignty,” IDF spokesman to the international press Lt. Col. Peter Lerner said on Twitter Sunday.

“Launching rockets from Lebanon in to Israel jeopardizes thousands of civilian lives in the north, a reality no sovereign state would accept. The IDF maintains the right to self defense and will operate accordingly against the perpetrators,” he added.

The Mevo’ot Hermon Regional Council, located east of Kiryat Shmona along the border, initially canceled its school bus routes and asked residents to stay home. But within half an hour after the rockets’ fall, local officials ordered a resumption of the school bus service.

“Everything is fine. We’re resilient, and we trust the army to protect us,” said Mevo’ot Hermon Mayor Benny Ben Muvchar.

While northern residents reported that no sirens had sounded ahead of the explosions, other reports claimed “Color Red” anti-rocket warning sirens had sounded in Kiryat Shmona and Safed Sunday morning.

Lebanese, Palestinian and Hezbollah flags on the northern side of Israel's border with Lebanon (photo credit: Hamad Almakt/Flash 90)

File photo: Lebanese, Palestinian and Hezbollah flags on the northern side of Israel’s border with Lebanon (photo credit: Hamad Almakt/Flash90/File)

Unlike the southern border with Gaza, the anti-rocket systems on the northern border are not active on a permanent basis. The systems are activated by the IDF only when tensions rise along the border. The rocket falls were a surprise to the security services, Israeli media reported Sunday morning.

The Katyusha is a WWII-era, Soviet-made 122-mm rocket favored by terror groups for its mobility.

The attack follows a series of incidents in recent months along the border.

Earlier this month, Master Sgt. Shlomi Cohen, 31, was shot and killed by a Lebanese Army soldier while driving along the border near the coastal town of Rosh Hanikra. The shooting happened near the spot where a bomb blew up an army jeep, injuring four soldiers, in August. Four Katyusha rockets were fired from Lebanon into Israel in late August.

AP contributed to this report.