Hezbollah on Wednesday threatened to retaliate after Israel's first reported air raid targeting a position of the Lebanese Shiite movement since the 2006 war.
The statement comes two days after Israeli warplanes struck a Hezbollah position in eastern Lebanon, amid fears that the region may be dragged into further conflict.
"On Monday night... the Israeli enemy's warplanes bombarded a Hezbollah position on the Lebanese-Syrian border, near the area of Janta in the Bekaa Valley" in eastern Lebanon, Hezbollah said.
Wednesday's statement was the group's first admission that it had been the target of the raid, although Lebanese sources had previously reported the attack.
"This new attack amounts to blatant aggression against Lebanon, its sovereignty and territory," the armed movement said, adding that "it will not stand without a response from the Resistance, which will choose the appropriate time, place and means".
It also said: "This aggression did not, thank God, cause any deaths or injuries. There was only some material damage."
Hezbollah, which brands itself a resistance movement against Israel, was formed in 1982 by Iran's Revolutionary Guards and was the principal actor in ending Israel's occupation of southern Lebanon in 2000.
Hezbollah is Lebanon's only movement that has not disarmed since the small Mediterranean country's brutal 15-year civil war ended in 1990.
It has bases in the south of Lebanon, the Bekaa Valley in the east and in its southern Beirut bastion.
The group denied earlier reports that Israel's raids had hit "artillery positions or missiles".
On Monday night, a Lebanese security source told AFP two raids had hit a Hezbollah target at the Lebanese-Syrian border.
Hezbollah's Al-Manar television channel had denied any raid had hit Lebanese territory.
- Israeli 'no comment' -
On Tuesday, Israeli officials refrained from commenting specifically on Monday night's raid, although they confirmed a policy of interdiction of suspected arms deliveries from Syria to Hezbollah.
"We are doing everything that is necessary in order to defend the security of Israel," Israeli Prime Minister Benjamin Netanyahu said.
"We will not say what we're doing or what we're not doing."
It was the first Israeli attack against Hezbollah in Lebanon since the 2006 war that killed more than 1,200 Lebanese, mostly civilians, and some 160 Israelis, mostly soldiers.
Residents said they saw flares light up the sky ahead of the raids which shook their houses, and that the strike had pounded Hezbollah positions on the hills overlooking the Lebanese border town of Nabi Sheet.
Hezbollah acknowledged last spring that it is sending fighters into neighbouring Syria to support President Bashar al-Assad's forces as they battle a nearly three-year uprising.
According to Waddah Charara, a sociology professor and author of "The State of Hezbollah", the raids could mark an important turning point.
Now "Israel can attack Lebanon because it knows there will be no reaction at the national level," Charara said.
The movement enjoyed widespread support in Lebanon during the 2006 conflict with Israel, but its popularity has diminished in recent years, and its decision to intervene in the Syrian conflict is controversial.
Syria has long provided arms and other aid to Hezbollah, and also served as a conduit for Iranian military aid to the movement.
In May, Israel launched two raids targeting what it said were arms convoys near Damascus destined for Hezbollah.
And on November 1 last year, there were reports of an Israeli strike against a Syrian air base where missiles to be supplied to Hezbollah were located.