An Israeli infantry force on Wednesday crossed the border fence near the Lebanese town of Mays and swept 50 meters from the fence without exceeding the Blue Line, the de facto Lebanon-Israel border established by the U.N. A security source said that the Israeli force had fired smoke grenades while Israeli warplanes were flying at medium altitude over the Lebanese borders. The Lebanese Army and the United Nations Interim Force in Lebanon (UNIFIL) are on a state of alert in anticipation of any further development, the source added.