JERUSALEM, Israel -- Israeli troops fired artillery shells at a Lebanese launch site early Tuesday in response to four Katyusha rockets fired just after midnight on northern Israel.
Several residents of the western Galilee heard the explosions, YNet reported. The 122-mm rockets damaged a chicken coop and hit a propane gas tank, but no one was injured.
The IDF Spokesman's Office issued a statement saying it views the incident as "serious" and holds the Lebanese government and Lebanese Army responsible for preventing rocket attacks on Israel.
Troops in the north were put on full alert. By midmorning, the Lebanese Army acknowledged that one rocket had been fired at Israel, AFP reported.
The IDF believes al Qaeda-affiliated splinter groups and/or Palestinian factions in Lebanon -- rather than Hezbollah -- have been responsible for the sporadic rocket attacks.
Hezbollah later denied any connection to the rocket attacks and an al Qaeda-affiliated group, the Abdullah azzam Brigade, claimed responsibility.
The IDF filed a complaint with UNIFIL -- the U.N. peacekeeping force patrolling Lebanon's southern border with Israel.
UNIFIL responded by denying any violation of U.N. Resolution 1701, issued with the ceasefire that ended the Second Lebanon War in the summer of 2006. UNIFIL said it is "working to restore normalcy," Beirut radio reported.
In the five-and-a-half years since the war, there have been sporadic rocket attacks from Lebanon (though none in the past two years) and a few border incidents.
In August 2010, Lebanese soldiers fired on a routine IDF patrol near the northern Israeli city of Metulla, killing Lt. Col. Dov Hariri and seriously injuring two other soldiers.
In a veiled threat earlier this month, Hezbollah spiritual leader Sheikh Hassan Nasrallah warned that an "Israeli-American attack on Iran or [Western] military involvement in Syria will lead to a regional war."
Since the U.N.-brokered ceasefire in 2006, the IDF estimates that Hezbollah has amassed up to 50,000 rockets and missiles.
Despite the presence of UNIFIL forces and the terms of Resolution 1701, Hezbollah -- part of the Lebanese unity government -- has rebuilt and strengthened its position in southern Lebanon, with support from Iran and Syria.