Israeli and Lebanese troops exchanged fire on their joint border Monday, both sides reported, offering conflicting accounts of who fired first, DPA reported.
An Israeli army spokeswoman told the German Press-Agency dpa that a routine Israeli border patrol unit was fired on from the Lebanese side. The Israeli patrol soldiers then returned fire, she said.
The Israeli army spokeswoman could not confirm a report of one killed on the Lebanese side.
Israel had complained to the United Nations Interim Force in Lebanon (UNIFIL), she said.
A Lebanese security official said Israeli troops had opened fire on a military base in southern Lebanon, prompting retaliatory fire. An Israeli patrol had fired on the base in the Wazzani border area, the source said.
The exchange of fire continued for several minutes, Lebanese radio stations said. The incident led to a state of alert among the Lebanese army.
In August 2010, two Lebanese soldiers, a Lebanese journalist and an Israeli officer were killed in a rare cross-border clash in Adaisseh, less than 10 kilometres to the west of Wazzani.
But gunfights have been extremely rare since the 2006 second Lebanon war, when Israel and Lebanon's Hezbollah movement engaged in 33 days of heavy combat.
In May, Palestinian refugees living in Lebanon and supporters marched toward the Israeli side of the border, prompting Israeli soldiers to open fire. Some 10 were killed.