© Reuters/ Cynthia KaramLebanon's Minister of Energy and Water Gebran Bassil smiles during an inteview with Reuters at his office in Beirut June 14, 2010.
Lebanon, technically at war with Israel, has warned in the past that it would "use all means" to defend its resource rights if Israel was found to be drilling within its borders.
Gebran Bassil told reporters at a media conference that Israel had discovered an underwater gas field in the Mediterranean sea only 4 km (2.5 miles) away from the border.
"This means, theoretically, that Israel is now able to reach Lebanese gas and that is a very grave situation," he said.
Barak Seri, the spokesman for Israel's Energy Ministry declined to comment.
Israel has made two of the world's largest offshore finds in the past decade, said to contain more than 800 billion cubic metres of gas. Texas-based Noble Energy is leading several international energy firms retrieving the new finds.
"We do not want to say a crisis would happen, but ... Israel would be able to dig horizontally. By doing that, it could reach the proven wells in Lebanon," Bassil said.
so called borders are checked, certain of the gas fields are within Palestinian areas, hence the relentless encroaching by Israel.