Israeli and Lebanese Army forces exchanged artillery fire across their border today. It's the most serious incident on the Israeli-Lebanese border since the war of 2006.
The Israeli military has confirmed one of its officers, a battalion commander with the rank of colonel, was killed in the incident. His family has been notified.
Lebanon says three of its soldiers and one journalist were killed.
Lebanese army sources claim an Israeli engineering unit crossed the border into Lebanese territory to clear trees which were obscuring the Israelis' view of a nearby Lebanese village.
Israel's military told ABC News its forces were operating on the Israeli side of the border. The Israeli army released the following statement:
"The soldiers were on routine activity in Israeli territory, in an area that lies between the 'Blue Line' (the internationally recognized border between Israel and Lebanon) and the security fence, thus within Israeli territory."
The Lebanese Army claims it fired warning shots; the Israelis said the patrol came under unprovoked fire.
The incident quickly escalated into a prolonged exchange of artillery fire. Lebanese sources say an Israeli military helicopter fired rockets destroying a Lebanese army position and an armoured vehicle.
Local Israeli television channels showed pictures of smoke and brush fires around the Lebanese village of al Adaisseh. The border area has been tense but quiet since the end of the Israeli-Hezbollah war of 2006 which resulted in over 1200 Lebanese and 160 Israeli deaths.
The truce agreement which ended the fighting saw the arrival of a 12,000-strong UN force to patrol the fragile peace. It is called UNIFIL and today senior officers called for both sides to show restraint.
UNIFIL spokesman Neeraj Singh said, "UNIFIL peacekeepers are in the area and are trying to ascertain the circumstances of the incident and any possible casualties. Our immediate priority at this time is to restore calm in the area."
So far Hezbollah forces which are known to operate near the border have played no part in the fighting.
Lebanese politicians were quick to condemn the Israelis with President Michel Suleiman urging his army to "confront any Israeli aggression whatever the sacrifices."
He repeated the accusation that Israeli forces had crossed the so-called Blue Line that separates the two countries. Israel's foreign ministry insisted later the Israeli soldiers had been acting in coordination with the UN and within Israeli territory and in a statement warned, "Israel holds the Lebanese government responsible for the grave incident, and warns of the consequences should these continue."