Israel said Friday it shelled a position belonging to the powerful Shiite movement Hezbollah inside Lebanon, in response to a blast targeting its troops along the border.
Hezbollah had threatened to strike back after an air raid in February, the first reported Israeli strike on one of its positions inside Lebanon since the brief but bloody summer war of 2006 between the arch-foes.
In Jerusalem, the military confirmed both Friday's blast and the shelling in response, saying it had acted after a border patrol was attacked by an explosive device.
Military spokesman Lieutenant Colonel Peter Lerner told reporters that an "armoured vehicle on patrol adjacent to the Israel-Lebanon border near Har Dov (Israel's term for the disputed Shebaa Farms) was attacked with an explosive device".
Israeli troops "responded by shelling Hezbollah positions and other suspicious locations," Lerner said.
He said that Hezbollah sites were not the only ones to be targeted and that "other suspicious positions along the border had also been hit", without giving further details.
He called it the "most severe instance of violation of the border that we've seen recently".
Lerner added that no Israeli troops were injured in the blast, but the three soldiers involved in the incident were taken to hospital for a precautionary medical check.
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A Lebanese security source had said earlier that "10 Israeli rockets hit an uninhabited border area and that there were no casualties".
Lebanon's official news agency NNA, meanwhile, reported "six shells fired (that hit) between Kfar Shuba and Halta in southeast Lebanon".
Tensions have been rising between Hezbollah and Israel over the deadly conflict in Syria, with Israel warning it will do "everything necessary" to prevent the transfer of advanced arms from Damascus to its Lebanese Shiite ally.
Late last month, Israeli warplanes bombarded a Hezbollah position on the Lebanese-Syrian border.
Israel neither confirmed nor denied carrying out the two February 24 strikes, but Hezbollah threatened to hit back over the air raid.
And on March 5, the Israeli army said it opened fire and hit two members of the Shiite group as they tried to plant a bomb near the Israeli-Syrian ceasefire line.
The army did not say at the time what weapons it had used to fire on the men.
Israel is bent on halting any transfer of weapons to Hezbollah, which has sent thousands of fighters across the border from Lebanon into Syria to aid Assad's regime as it battles Sunni-led rebels.
Syria has long provided arms and other aid to Hezbollah, and served as a conduit for Iranian military aid to the movement, which battled Israel to a bloody stalemate in the 2006 war.