A Hezbollah statement said its anti-aircraft batteries targeted the Israeli planes over the central and western sectors of the southern border zone.

Israeli warplanes earlier caused supersonic booms from the south to the north of the country, AFP correspondents said.

The fighter bombers set off two loud booms at about 10:55 amover the southern region of Marjayoun before again breaking the sound barrier over the nearby port city of Tyre, they said.

The jets then caused more booms over the Shebaa Farms, a border area where Hezbollah is leading a guerrilla war against occupying Israeli forces.

The warplanes then broke the sound barrier over the eastern city of Baalbek, a Hezbollah stronghold, before zooming up north to do the same beyond the port city of Tripoli, close to the Syrian border.

The United Nations expresssed concern over the "large" number of Israeli overflights and asked the country's military to respect the UN-drawn border line between the two states.

"The UNFIL (UN Interim Forces in southern Lebanon) force commander is seriously concerned about the large number of overflights that have taken place over Lebanon today," said a UN statement.

"He has protested this to the Israeli Defense Forces (IDF) and asked them to fully respect the blue line," demarcating the borders between Lebanon and Israel, it added.

Hezbollah -- backed by Lebanon, Syria and Iran -- has threatened Israel with "costly" reprisals if its air force continues its almost daily violations of Lebanese airspace despite previous UN condemnation.

Overnight Sunday, Israeli jets staged mock air raids over Beirut in retaliation for Hezbollah fire that killed one person and wounded five others in northern Israel earlier in the day.

Hezbollah said it only fired anti-aircraft guns at Israeli warplanes overflying Lebanon, but Israel countered by saying Hezbollah had fired across the border in a deliberate attack, swiftly mounting a retaliatory strike.

That prompted Lebanon to open a diplomatic campaign to prevent Israel from carrying out threats of retaliatory air strikes.

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