Lebanese troops and an Israeli army patrol exchanged fire on their shared border last night in the first such incident since Lebanon deployed regular forces after Israel's war against Hezbollah guerrillas.
The clash began after the Lebanese troops shot in the air as the patrol crossed a security fence near the border village of Avivim to search for explosives planted by Hezbollah.
"We called for them to stop firing, they shot at us and we returned fire," an Israeli source said, adding that the Israeli patrol had not crossed into Lebanese territory.
There were no casualties in the clash, which was confirmed by the Lebanese army.
"An Israeli bulldozer crossed into south Lebanon tonight. Our forces opened fire at it. It pulled back and there was a brief exchange of fire," a Lebanese army spokesman said.
A spokesman for Unifil, a UN peacekeeper force in southern Lebanon that was boosted after last year's war, confirmed the exchange was initiated by the Lebanese army after an Israeli bulldozer crossed the border fence "in an apparent attempt to clear mines between the Blue Line [border] and the fence".
"We characterise this as a serious incident between the Lebanese army and the IDF (Israeli Defense Forces)," the spokesman said.
Irish troops are among the international forces serving with Unifil in the area.
Lebanon deployed its army along the frontier as part of a UN-brokered ceasefire that ended Israel's 34-day offensive against Hezbollah. The border has been largely quiet since then.
Israel ordered the searches around Avivim after discovering four explosive devices on the border on Monday. Israeli officials accused Hezbollah of planting the bombs recently, but Hezbollah said it planted them before the July-August war.